Abstract: Through impact tests and uniaxial tensile tests, the effects of neutron irradiation on the tensile properties and impact performance of 15 MnTi steel are studied. Impact energy of parent metal and heat-affected zone（HAZ） of 15 MnTi steel and tension curves of 15 MnTi steel at room temperature and 300℃ before and after irradiation with neutron irradiation temperature 50℃ and cumulative fast neutron flux 1.5066×10¹⁸ cm^-2 are obtained. Results show that the neutron irradiation increases the ductile brittle transition temperature（DBTT） of the parent metal and HAZ of 15 MnTi steel, in which the parent metal increases more than HAZ, while the upper shelves of impact energy change little; yield strength and tensile strength of the parent metal of 15 MnTi steel increase after irradiation, especially the yield strength at room temperature, but the tensile properties at high temperature change little.