Abstract: To improve the accuracy of the software reliability evaluation,more failure data of programs under evaluation are needed.This paper presents a fault injection mechanism for software reliability evaluation.The program fault type distribution,fault location distribution,fault occurring time distribution and inputs of the program are considered during the fault injection scheme generation.Therefore,the proposed mechanism can reasonably emulate the program failure.A fault injection scheme generator is implemented and integrated into an in-house PIN-based dynamic software fault injection system.The TINY compiler,LZ77 and CRC32 programs are chosen as target applications to verify the efficiency and reasonability of the proposed fault injection mechanism.Two groups of failure data are collected by testing and fault injection,respectively,and the Jelinski-Moranda model is used to get two sets of reliability attributes.The experimental results show that the fault injection based software reliability evaluation method is at least as efficient and reasonable as the conventional test based methods.It is more suitable for large scale programs,and the exponential distribution assumption is better for fault occurring time distribution.