Abstract: The effects of annealing temperature on the microstructure and tensile properties of cold drawn 0Cr21Ni6Mn9N austenitic stainless steel tubes were investigated by microstructure observation and tensile testing. The results show that when the test steel tubes were annealed at temperature above 600 ℃, the Cr 23C6 particles precipitated on the grain boundary, annealing twins formed in the grain and twins intensity increased as the temperature increased. When the test tubes were treated in temperature range of 200-550 ℃, the strength of the steel tubes increased slightly, but the plasticity increased little. When the heat treatment temperature was higher than 600 ℃, the strength of steel tubes decreased obviously and the plasticity increased observably