Abstract: Studied are the effects by the solution treatment temperature on the structure and mechanical properties of the S32168 stainless steel.As a result it is revealed that after the solution treatment the structure of the said stainless steel is composed by equiaxed grains,and there exist annealing twins;when the solid solution temperature is≥1 080℃,the precipitates in the stainless steel are almost completely dissolved into the matrix;when the solid solution temperature is 1 040~1 120℃,the grain size grows along with the increase of the temperature,and the growth activation energy is 563.49 kJ/mol,and within this temperature range,the grain size and the room temperature mechanical properties of the S32168 stainless steel conform to the Hall-Petch relationship:the stainless steel strengthening mechanism is mainly fine grain strengthening;and along with the increase of the temperature,the fracture mode of S32168 stainless steel is transforming from the brittle fracture to the ductile fracture.