Abstract: The strain induced precipitation behavior of steel 33Mn2V for oil well tubes in austenite region in the range of 600-950 ℃ was investigated by the stress relaxation method using Gleeble2000 thermal-mechanical simulator.The results show that the shape of precipitation-temperature-time (PTT) is a “double C” curve;the “nose” temperatures of the precipitation curve are about 850 ℃ and 650 ℃,respectively.Two types of precipitates in austenite,cubic and oblong ovate,were observed.The cubic particles are mostly TiN undissoved during reheating,while the oblong ovate precipitates are complex TixV1-xCyN1-y formed by V,C and N epitaxially growing on the substrate of TiN particle.