Abstract: Code reuse is an important way of software reuse．Software engineers need to understand the code functions before they reuse the code．A Code Function Mining (CFM) method based on static code analysis and LDA technologies was proposed．CFM method is a code-oriented method for mining,filtering,organizing and describing topics．The output of CFM method is a hierarchy structure of functional topics with descriptions．Topic descriptions can help better learn code functions and the hierarchy structure can help better understand code functions from different abstraction levels．CFM method can be used as a supplement of traditional methods based on topic modeling technology to make up for the lack of semantic analysis of topics. CFM method includes four parts:Topic Mining,Topic Filtering,Topic Organizing,Topic Describing．A CFM tool based on CFM method can automatically analyze code and show the function topic hierarchy to users through Web page．To verify the validity of CFM method,the experimental analysis was also presented on several key algorithms in it.

Key words: Software code,Static code analysis,LDA,Code function mining