diff --git a/conf.py b/conf.py
index 46a5f23..1588492 100644
--- a/conf.py
+++ b/conf.py
@@ -137,6 +137,42 @@
     #
     # 'figure_align': 'htbp',
 }
+on_rtd = os.environ.get('READTHEDOCS', None) == 'True'
+
+if on_rtd:
+    latex_elements = {
+    # The paper size ('letterpaper' or 'a4paper').
+    #'papersize': 'letterpaper',
+    # The font size ('10pt', '11pt' or '12pt').
+    #'pointsize': '10pt',
+    # Additional stuff for the LaTeX preamble.
+    'preamble': r'''
+    \hypersetup{unicode=true}
+    \usepackage{CJKutf8}
+    \DeclareUnicodeCharacter{00A0}{\nobreakspace}
+    \DeclareUnicodeCharacter{2203}{\ensuremath{\exists}}
+    \DeclareUnicodeCharacter{2200}{\ensuremath{\forall}}
+    \DeclareUnicodeCharacter{2286}{\ensuremath{\subseteq}}
+    \DeclareUnicodeCharacter{2713}{x}
+    \DeclareUnicodeCharacter{27FA}{\ensuremath{\Longleftrightarrow}}
+    \DeclareUnicodeCharacter{221A}{\ensuremath{\sqrt{}}}
+    \DeclareUnicodeCharacter{221B}{\ensuremath{\sqrt[3]{}}}
+    \DeclareUnicodeCharacter{2295}{\ensuremath{\oplus}}
+    \DeclareUnicodeCharacter{2297}{\ensuremath{\otimes}}
+    \begin{CJK}{UTF8}{gbsn}
+    \AtEndDocument{\end{CJK}}
+    ''',
+    }
+else:
+    latex_elements = {
+        'papersize' : 'a4paper',
+        'utf8extra' : '',
+        'inputenc'  : '',
+        'babel'     : r'''\usepackage[english]{babel}''',
+        'preamble' : r'''
+        \usepackage{ctex}
+        ''',
+    }
 
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title,