actually I didn't use TexMaker on Mac before. I use TexShop and I thinks it is convenient to use to type in Chinese.
If you use TexShop, please set your unicode to UTF-8 in preference.
Here is the code for reference:
\usepackage[T1]{fontenc}
\usepackage{xeCJK}
\setCJKmainfont{BiauKai}
\newCJKfontfamily\Kai{魏碑-繁} % Set main font in your document.
\newCJKfontfamily\ChCal{行楷-繁} % Set a new font so that you can
\newCJKfontfamily\ChBlack{蘭亭黑-繁} % change the font in the document.
\XeTeXlinebreaklocale "zh" % Following set to break line automatically.
\XeTeXlinebreakskip = 0pt plus 1pt
\usepackage{xltxtra,xunicode}
\begin{document}
中文字測試
\end{document}
If you'd like to change your font, just use
\ChCal{行楷-繁}
command, for example.
In TexShop, you can use the font directly installed on your Mac. You don't need to download another set of font, like CJK font by Han-tsong Wang.