The invention provides a software clustering-based source code function search method. The method comprises the following steps of: inputting a source code; carrying out grammar inspection on the source code and acquiring class information of the source code; and completing a search process through two modules, wherein the two modules comprise a software clustering module and a function search module, the software clustering module is used for screening an entity from acquired class information, constructing an entity index, extracting a feature, constructing a feature vector, screening information through hierarchical clustering, and storing a result, and the function search module is used for constructing an input set from the acquired class information, completing subject analysis, constructing an index and storing the index. The method provided by the invention can effectively enhance the software clustering result, and has good guiding function in the aspects of practical source code reading and system maintenance. Developers can use the method to guide the previous exploration, accelerating project understanding and enhance the development efficiency. And through further development, the method can be used for completing the multiplexing of function modules.