diff --git a/lib/homeland/sanitize/topic_scrubber.rb b/lib/homeland/sanitize/topic_scrubber.rb
index f79249288d..8a88715f32 100644
--- a/lib/homeland/sanitize/topic_scrubber.rb
+++ b/lib/homeland/sanitize/topic_scrubber.rb
@@ -9,6 +9,7 @@ def initialize
         self.tags = %w[
           p br img h1 h2 h3 h4 h5 h6 blockquote pre code b i del
           strong em table tr td tbody th strike del u a ul ol li span hr
+          sub sup
         ]
 
         self.attributes = %w[
diff --git a/test/helpers/application_helper_test.rb b/test/helpers/application_helper_test.rb
index a0aa33274a..27ebdfd865 100644
--- a/test/helpers/application_helper_test.rb
+++ b/test/helpers/application_helper_test.rb
@@ -16,6 +16,10 @@ def current_page?(url)
     assert_equal "<p>Hello world alert()</p>", sanitize_markdown("<p>Hello world <script>alert()</script></p>")
   end
 
+  test "sanitize_markdown sup and sub" do
+    assert_equal "<p>L<sup>A</sup>T<sub>E</sub>X 结构化的路径覆盖（C<sub>i</sub>(k)-覆盖）</p>", sanitize_markdown("<p>L<sup>A</sup>T<sub>E</sub>X 结构化的路径覆盖（C<sub>i</sub>(k)-覆盖）</p>")
+  end
+
   test "admin?" do
     user = create :user
     admin = create :admin
diff --git a/test/lib/markdown_test.rb b/test/lib/markdown_test.rb
index 68ae6c48f8..cdf236d27b 100644
--- a/test/lib/markdown_test.rb
+++ b/test/lib/markdown_test.rb
@@ -243,6 +243,10 @@ def foo
     end
   end
 
+  test "sup and sub" do
+    assert_markdown_render %(<p>L<sup>A</sup>T<sub>E</sub>X 结构化的路径覆盖（C<sub>i</sub>(k)-覆盖）</p>), "L<sup>A</sup>T<sub>E</sub>X结构化的路径覆盖（C<sub>i</sub>(k)-覆盖）"
+  end
+
   test "footnotes" do
     assert_markdown_render %(<p>some ^strikethrough^</p>), "some ^strikethrough^"
   end