In this paper we studied the effects of temperature and dissolved oxygen on crack growth rate in 316L type stainless steel used as auxiliary pipe in nuclear power systems in high purity water under the pressure of 15.5MPa.This experiment compares the crack growth rate of 316L in the temperature range of 200℃-325℃ with different contents of dissolved oxygen.Experimental results show that the crack growth rate of this material in the oxygenated water is significantly higher than that in deoxygenated water environment and the rate increases with the temperature rise.Meanwhile,we find that this effect will become more apparent with the increasing of temperature.