Abstract: Software defect is the key measure of software reliability,and predicting defect is also one of the core topics of software quality evaluation.Based on analysis of mechanism of software defect growth,the states of defect are divided into hidden,be detected and repaired.Considering the combined effect of distrustable factors and constrained factors,the differential equation model for defect states transferring is proposed in this paper.The stability of equilibrium point and boundary condition of distrustable factors are also analyzed.Meanwhile,a real project of NASA is analyzed,the hidden defects are estimated by the record of detected and repaired defect,and the results are exemplified the rationality of the model.

Key words: defect, distrustable factor, differential equation, prediction