In order to evaluate the flow field characteristics and infrared radiation characteristics of the anti-ship missile nozzle in supersonic flight state, the nozzle of “Xiongfeng-3”anti-ship missile is taken as the research object and the corresponding two-dimensional simulation model is established in this paper. The calculation results of the flow field show that the condensed phase particles have a significant effect on the flow field characteristics of the jet. Compared with the pure gas phase, the length of the axial high-temperature zone increases obviously with the addition of condensed particles, and the Mach number decreases faster. The calculation results of infrared radiation characteristics show that the infrared radiation characteristics of the nozzle and wake show strong symmetry. The maximum radiation intensity appears when the yaw angle is 60°，and the radiation intensity reaches 103.68 W/sr.