Software fault detection rate and total number of initial faults are two important factors that influence software reliability in the traditional software reliability growth G-O model.In order to increase the reliability

the fact that new errors may be introduced during error correction process of software is considered.The total number of potential faults and fault detection rate are defined as a function of time

an improved G-O model is proposed

and its analytical method is given.The G-O model before and after improvement are compared and verified by some examples.