diff --git a/docs/数学进阶/numerical.en.md b/docs/数学进阶/numerical.en.md
index 0bb8bf68..98c8e4d2 100644
--- a/docs/数学进阶/numerical.en.md
+++ b/docs/数学进阶/numerical.en.md
@@ -17,7 +17,7 @@ The designers of this course have also written an open source textbook for this
 ## Course Resources
 
 - Course Website: <https://github.com/mitmath/18330>
-- Textbook: <https://fncbook.github.io/fnc/frontmatter.html>
+- Textbook: <https://fncbook.com>
 - Assignments: 10 problem sets
 
 ## Personal Resources