bibliographiesbibtexbooksfontsizeheader-footer
I need to change the font size of reference title in ctexbook. An obvious way is redefining the \bibname macro. However, that would change the heading as well. For example,
\renewcommand{\bibname}{\zihao{2} 参考文献}
leads to 
So, my question is how to change the font size of the title without affecting the heading. Since biblatex is incompatible with many other packages, I would prefer non-biblatex solution.
The use of the [explicit] option to titlesec forces the user to input #1 for the title format. You'll note a reference to \LARGE#1 within the definition of \titleformat for \chapter (both). Adjust this to suit your needs.
Below I've updated the font reference so you can (re)define \chaptertitlefont:
\documentclass{book}
\usepackage[explicit]{titlesec}
\usepackage{lmodern,lipsum}
\newlength\chapnumb
\setlength\chapnumb{4cm}
\newcommand{\chaptertitlefont}{\normalfont\sffamily\Huge}
\titleformat{\chapter}[block]
{\normalfont\sffamily}{}{0pt}
{\parbox[b]{\chapnumb}{%
\fontsize{120}{110}\selectfont\thechapter}%
\parbox[b]{\dimexpr\textwidth-\chapnumb\relax}{%
\raggedleft%
\hfill{\chaptertitlefont#1}\\
\rule{\dimexpr\textwidth-\chapnumb\relax}{0.4pt}}}
\titleformat{name=\chapter,numberless}[block]
{\normalfont\sffamily}{}{0pt}
{\parbox[b]{\chapnumb}{%
\mbox{}}%
\parbox[b]{\dimexpr\textwidth-\chapnumb\relax}{%
\raggedleft%
\hfill{\chaptertitlefont#1}\\
\rule{\dimexpr\textwidth-\chapnumb\relax}{0.4pt}}}
\begin{document}
\chapter*{A Long Title for an Unnumbered Test Chapter}
\lipsum[4]
\chapter{Introduction}
\lipsum[4]
\end{document}
The above changes the font to \Huge. If you want larger font sizes, see Fonts larger than \Huge?
Or with the package titlesec. This allows to change the format in a way more flexible.
\documentclass{book}
\usepackage{titlesec}
\titleformat{\chapter}[display]{\bfseries\huge}{\chaptertitlename\space\thechapter}{20pt}{\huge}{}
\begin{document}
\chapter{THIS CHAPTER TITLE IS TOO LONG}
Text
\chapter{THIS CHAPTER TITLE IS OTHER TOO LONG}
Text\newpage Text
\end{document}
Best Answer
Motivated by Gonzalo Medina's answer from How to remove the “References” title, I use
\patchcmdto modify the definition of\thebibliography.gives what I want.