diff --git a/Cargo.lock b/Cargo.lock
index 08e5f2d..91e6dd7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -226,6 +226,7 @@ dependencies = [
  "clap",
  "epub",
  "html2md",
+ "regex",
 ]
 
 [[package]]
diff --git a/Cargo.toml b/Cargo.toml
index 0f66d43..295ec2b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,3 +8,4 @@ anyhow = "1.0.96"
 clap = { version = "4.5.30", features = ["derive"] }
 epub = "2.1.1"
 html2md = "0.2.15"
+regex = "1.11.1"
diff --git a/src/lib.rs b/src/lib.rs
index 449e184..b378a06 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,6 @@
 use epub::doc::{EpubDoc, NavPoint};
 use html2md::parse_html;
+use regex::{Captures, Regex};
 use std::collections::HashMap;
 use std::fs;
 use std::io::{Read, Seek};
@@ -9,28 +10,31 @@ pub fn convert_epub_to_mdbook(
     epub_path: impl AsRef<Path>,
     output_dir: Option<impl AsRef<Path>>,
 ) -> anyhow::Result<()> {
-    let book_name = epub_path.as_ref().with_extension("");
-    let book_name = book_name.file_name().unwrap().to_str().unwrap();
-    let pwd = PathBuf::from(".");
+    let epub_path = epub_path.as_ref();
+    if !epub_path.is_file() {
+        return Err(anyhow::anyhow!("{} is not a file", epub_path.display()));
+    }
+    let book_name = epub_path.with_extension("");
+    let book_name = book_name.file_name().unwrap().to_string_lossy().to_string();
     let output_dir = match output_dir {
-        Some(output_dir) => output_dir.as_ref().join(book_name),
-        None => pwd.join(book_name),
+        Some(output_dir) => output_dir.as_ref().join(&book_name),
+        None => PathBuf::from(".").join(&book_name),
     };
 
     fs::create_dir_all(output_dir.join("src"))?;
 
-    let mut doc = EpubDoc::new(&epub_path)?;
+    let mut doc = EpubDoc::new(epub_path)?;
     let title = if let Some(title) = doc.metadata.get("title") {
-        title.first().unwrap_or(&book_name.to_string()).clone()
+        title.first().cloned().unwrap_or(book_name)
     } else {
-        book_name.to_string()
+        book_name
     };
     let creator = doc.metadata.get("creator").and_then(|v| v.first().cloned());
 
-    let (toc, html_files) = toc_to_md(&doc, &title)?;
+    let (toc, html_to_md) = toc_to_md(&doc, &title)?;
     fs::write(output_dir.join("src/SUMMARY.md"), toc)?;
 
-    extract_chapters_and_resources(&mut doc, &output_dir, &html_files)?;
+    extract_chapters_and_resources(&mut doc, &output_dir, &html_to_md)?;
     write_book_toml(&output_dir, &title, creator)?;
     Ok(())
 }
@@ -45,7 +49,7 @@ pub fn nav_point_to_md(
         "{}- [{}]({})\n",
         "  ".repeat(indent),
         nav.label,
-        file.to_str()?
+        file.to_string_lossy()
     );
     for child in &nav.children {
         if let Some(child_md) = nav_point_to_md(child, indent + 1, html_files) {
@@ -62,41 +66,53 @@ pub fn toc_to_md<R: Read + Seek>(
     let toc = doc.toc.clone();
 
     let mut markdown = format!("# {}\n\n", title);
-    let html_files = doc
+    let html_to_md = doc
         .resources
         .iter()
         .filter(|(_, (_, mime))| mime == "application/xhtml+xml")
         .map(|(_, (path, _))| (path.clone(), path.with_extension("md")))
         .collect::<HashMap<PathBuf, PathBuf>>();
     for nav in toc {
-        if let Some(md) = nav_point_to_md(&nav, 0, &html_files) {
+        if let Some(md) = nav_point_to_md(&nav, 0, &html_to_md) {
             markdown.push_str(&md);
         }
     }
-    Ok((markdown, html_files))
+    Ok((markdown, html_to_md))
 }
 
 pub fn extract_chapters_and_resources<R: Read + Seek>(
     doc: &mut EpubDoc<R>,
     output_dir: impl AsRef<Path>,
-    html_files: &HashMap<PathBuf, PathBuf>,
+    html_to_md: &HashMap<PathBuf, PathBuf>,
 ) -> anyhow::Result<()> {
     let output_dir = output_dir.as_ref();
     let src_dir = output_dir.join("src");
-
+    let re = Regex::new(r#"\[[^\]]+\]\(([^)]+)\)"#).unwrap(); // [abc](abc.html)
     for (_, (path, _)) in doc.resources.clone().into_iter() {
         let content = match doc.get_resource_by_path(&path) {
             Some(content) => content,
             None => continue,
         };
 
-        if let Some(path) = html_files.get(&path) {
+        if let Some(path) = html_to_md.get(&path) {
             let target_path = src_dir.join(path);
             if let Some(parent) = target_path.parent() {
                 fs::create_dir_all(parent)?;
             }
             let html = String::from_utf8(content)?;
             let markdown = parse_html(&html);
+            let markdown = re
+                .replace_all(&markdown, |caps: &Captures| {
+                    let link = caps[1].to_string();
+                    let ori = caps[0].to_string();
+                    if let Some(md_path) = html_to_md.get(&PathBuf::from(&link)) {
+                        let md_path = md_path.to_string_lossy().to_string();
+                        ori.replace(&link, &md_path)
+                    } else {
+                        ori
+                    }
+                })
+                .to_string();
             fs::write(target_path, markdown)?;
         } else {
             let target_path = src_dir.join(&path);
@@ -123,3 +139,18 @@ pub fn write_book_toml(
     fs::write(output_dir.join("book.toml"), toml_content)?;
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_replace_links() {
+        let markdown = r"[hello](hello.html)";
+        let re = Regex::new(r#"\[[^\]]+\]\(([^)]+)\)"#).unwrap();
+        let markdown = re.replace_all(&markdown, |caps: &Captures| {
+            let link = caps[1].to_string();
+            caps[0].replace(&link, "hello.md")
+        });
+        assert_eq!(markdown, "[hello](hello.md)");
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index ce38a4e..ec905d2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,7 +7,7 @@ use epub2mdbook::convert_epub_to_mdbook;
 struct Args {
     /// The path to the input EPUB file
     #[clap(short, long)]
-    input_epub_path: PathBuf,
+    input_epub: PathBuf,
     /// The path to the output directory
     #[clap(short, long)]
     output_dir: Option<PathBuf>,
@@ -15,7 +15,7 @@ struct Args {
 
 fn main() -> anyhow::Result<()> {
     let args = Args::parse();
-    convert_epub_to_mdbook(args.input_epub_path, args.output_dir)?;
+    convert_epub_to_mdbook(args.input_epub, args.output_dir)?;
     println!("Conversion completed successfully!");
     Ok(())
 }