Abstract: The cold deformation behavior of 302HQA stainless steel was systematically investigated through compress tests at room temperature. By means of microstructure and X-ray diffraction analysis, deformation-induced martensite transformation (DIMT) was found in this alloy during the cold forming process. The result of magnetic measurement shows that the amount of deformation-induced martensite increases with the increasing of plastic strain. When the plastic strain is lower than 30%, the amount of martensite increases with the increasing of strain rate, while the plastic strain is up to 50%, the amount of deformation-induced martensite decreases with the increasing of strain rate due to the effect of deformation-induced heat accumulation.