1、下载colordiff http://download.csdn.net/detail/qiaoning13256/8743773
2、安装Colordiff
3、把/usr/local/bin/colordiff 拷贝到某一个文件目录下，例如/Users/username/
sudo cp /usr/local/bin/colordiff /Users/username/
4、chmod u+x /Users/username/colordiff
5、修改~/.subversion/config文件
[helpers]
diff-cmd = /Users/username/colordiff
搞定！
原文：http://blog.csdn.net/qiaoning13256/article/details/46044681