LaTeX中的字体大小一般都要pt做单位, 跟我们平时熟悉的四号, 五号字格式不同, 下面列出它们之间的的对于关系.

在印刷出版上,中文字号制与点数制的对照关系如下:
% \begin{macro}{Chinese Font Size}
% 1770年法国人狄道(F.A.Didot)制定点数制,规定1法寸为72点,即:1点=0.3759毫米。
% 狄道点数制在法国、德国、奥地利、比利时、丹麦、匈牙利等国比较流行。
% 1886年全美活字铸造协会以派卡(pica)为基准制定派卡点数制,规定1pica=12point(点),即:
% \fbox{1点=0.013837英寸=0.35146毫米}\\
% 20世纪初派卡点数制传入我国,并得到逐步推广。在实用中对常用点数以号数命名而产生了号数制,
% 二者换算如下(以pt代表“点”):\\
% \begin{center}
% \begin{tabular}{r@{\ =\ }l}
% 初号& 42pt\\
% 小初号& 36pt\\
% 一号& 28pt\\
% 二号& 21pt\\
% 小二号& 18pt\\
% 三号& 15.75pt\\
% 四号& 14pt\\
% 小四号& 12pt\\
% 五号& 10.5pt\\
% 小五号& 9pt\\
% 六号 & 7.875pt\\
% 七号 & 5.25pt
% \end{tabular}
% \end{center}
以下内容为程序代码:
\newcommand{\chuhao}{\fontsize{42pt}{\baselineskip}\selectfont}
\newcommand{\xiaochuhao}{\fontsize{36pt}{\baselineskip}\selectfont}
\newcommand{\yihao}{\fontsize{28pt}{\baselineskip}\selectfont}
\newcommand{\erhao}{\fontsize{21pt}{\baselineskip}\selectfont}
\newcommand{\xiaoerhao}{\fontsize{18pt}{\baselineskip}\selectfont}
\newcommand{\sanhao}{\fontsize{15.75pt}{\baselineskip}\selectfont}
\newcommand{\sihao}{\fontsize{14pt}{\baselineskip}\selectfont}
\newcommand{\xiaosihao}{\fontsize{12pt}{\baselineskip}\selectfont}
\newcommand{\wuhao}{\fontsize{10.5pt}{\baselineskip}\selectfont}
\newcommand{\xiaowuhao}{\fontsize{9pt}{\baselineskip}\selectfont}
\newcommand{\liuhao}{\fontsize{7.875pt}{\baselineskip}\selectfont}
\newcommand{\qihao}{\fontsize{5.25pt}{\baselineskip}\selectfont}

%%%%%%%%%%%%%%%%%%

另外一种办法:

CODE


\usepackage{CJK}
\usepackage{ifthen}

\newcommand{\CJKfontsize}[4]{ %
\fontsize{ #1}{ #2 plus#3 minus #4}\selectfont}
\newcommand\zihao[1]{ %
\ifthenelse{\equal{ #1}{0}}{ %
\CJKfontsize{42bp}{50.4pt}{.5pt}{.3pt}}{}%
\ifthenelse{\equal{ #1}{0-}}{ %
\CJKfontsize{36bp}{43.2pt}{.5pt}{.3pt}}{}%
\ifthenelse{\equal{ #1}{1}}{ %
\CJKfontsize{26bp}{31.2pt}{.5pt}{.3pt}}{}%
\ifthenelse{\equal{ #1}{1-}}{ %
\CJKfontsize{24bp}{28.8pt}{.5pt}{.3pt}}{}%
\ifthenelse{\equal{ #1}{2}}{ %
\CJKfontsize{22bp}{26.4pt}{.5pt}{.3pt}}{}%
\ifthenelse{\equal{ #1}{2-}}{ %
\CJKfontsize{18bp}{21.6pt}{.3pt}{.2pt}}{}%
\ifthenelse{\equal{ #1}{3}}{ %
\CJKfontsize{16bp}{19.3pt}{.3pt}{.2pt}}{}%
\ifthenelse{\equal{ #1}{3-}}{ %
\CJKfontsize{15bp}{18pt}{.3pt}{.2pt}}{}%
\ifthenelse{\equal{ #1}{4}}{ %
\CJKfontsize{14bp}{16.8pt}{.3pt}{.2pt}}{}%
\ifthenelse{\equal{ #1}{4-}}{ %
\CJKfontsize{12bp}{14.4pt}{.3pt}{.2pt}}{}%
\ifthenelse{\equal{ #1}{5}}{ %
\CJKfontsize{10.5bp}{12.6pt}{.3pt}{.2pt}}{}%
\ifthenelse{\equal{ #1}{5-}}{ %
\CJKfontsize{9bp}{10.8pt}{.2pt}{.1pt}}{}%
\ifthenelse{\equal{ #1}{6}}{ %
\CJKfontsize{7.5bp}{9pt}{.2pt}{.1pt}}{}%
\ifthenelse{\equal{ #1}{6-}}{ %
\CJKfontsize{6.5bp}{7.8pt}{.2pt}{.1pt}}{}%
\ifthenelse{\equal{ #1}{7}}{ %
\CJKfontsize{5.5bp}{6.6pt}{.1pt}{.1pt}}{}%
\ifthenelse{\equal{ #1}{8}}{ %
\CJKfontsize{5bp}{6pt}{.1pt}{.1pt}}{}}


然后:

CODE


\zihao{5}这是五号字。 \zihao{4-}这是小四号字。 \\
\zihao{3}这是三号字。 \zihao{0}这是初号。