Abstract: Mice were treated by heat stress at the temperature 42℃ and one hour per day using incubator, and the sustaining systemic heat stressed animal model were established by this way. The control group and heat stress group mice were killed by cervical dislocation, when they were treated duration of heat stress to the day 8, 13, 21and 35, and the percentage of abnormal sperm in the epididymis was detected by using the modified Papanicolaou staining method, and the expression of HSP70 in the epididymis detected by immunofluorescence histochemistry and western blot analysis methods. The result showed: the percentage of abnormal sperm in the epididymis of heat stress group was increased with the prolongation of heat stress time, and was obviously higher than the control group; There was a strong expression of HSP70 in the control group(+++), however, the expression of HSP70 in the epididymis was weakened with the prolongation of heat stress time, 35d after the heat stress there was a very weak expression(±). The result indicated: The function of epididymis were damaged by heat stress, and the sperm deformity rate in the mice epididymis was increased; HSP70 in the epididymis was non heat inducible, it may played special effect in maturation process of epididymis sperm..