Abstract: The effect of temperature on the content of deformed martensite in austenitic stainless steel was studied by pretension test under different low temperature environments, and the influence of different deformed martensite content on the mechanical properties of the material was analyzed. The results show that under the same deformation and strain rate conditions, the lower the temperature, the more deformed martensite produced by the material. The more deformed martensite would harden the material and increase the strength, and led to the crack propagation rate at the notch of the impact specimen was accelerated and the impact toughness was reduced.