Abstract: In software fault diagnosis process,the most costly and time-consuming is software fault location．In order to help tester locate software fault,with guidance of layering design thought,based on the complex relationship between software and its various modules and codes,this paper proposed the software failure propagation model based on topological graph through analysis of the historical data of the corresponding relationships between software fault and its phenomenon,making it possible to use the topology graph model to describe the software fault phenomenon.Through the topological graph model,the software fault propagation model can be converted into an easier fault detection model based on the bipartitie graphs．Then,an algorithm is designed based on greedy strategy according to this model.This algorithm solves the problem of the minimum coverage solution based on the bipartitie graphs．The result of this solution describes the set of assumed reasons for software faults,finds the corresponding module to the fault through the analysis of the relationship between the fault and the software modules,and thus to achieve fault location．Experiments show that this method of software fault location is effective.

Key words: Software fault detection,Software fault location,Layering model,Bipartitie graph,Minimum coverage