It was not sufficient to predict the software fault based on partial phases of software development process or some metrics by analyzing the current fault predicting methods.This paper proposed to build a fault predicting model based on BBNs (Bayesian Belief Networks) by using the information of software development process.Based on a simple BBNs fault prediction model

a general fault prediction model was proposed by expanding the basic node.We brought forward that the software metrics and experts' knowledge could be used to determine the node status probability distribution.The simulation experiment proved that this model with good fault predicting ability coincided with the real case.