两者在中文中都有分类的意思，具体区别我查了半天还是有点迷糊，有一个比较简单的说法

1. categorize 的含义是分成不同的小组，一般有按照功能分类的含义

• 　　Lindsay, like his films, is hard to categorize.
• 　　Her first novel defies easy categorization.

2. classify 是按照属性或者标签排序

• 　　Classify them by branch, region, and year.
• 　　Men in the post office classify mail according to places it is to go.

相关引用：

http://www.googolpower.com/content/articles/categorizing-classifying

http://www.usingenglish.com/forum/threads/1721-classify-vs-categorize

* When you classify, you group together several things that have something in common.

* When you tell how the parts of the group are alike, you categorize them.