Abstract: This paper presents the simulation of heat flux on complex-shaped lunar detector in thermal tests. The optimization design of infrared lamp array is realized by using duel-objective and variable metric grid strategy based on genetic algorithm and complex algorithm. The heat flux distribution database is generated based on the calculation of the heat flux distribution of a single lamp. The problem of the heat flux reflection from the reflective baffles is thus solved. A simulation method for calculating the infrared lamp array heat flux is established on the basis of these models. The method enjoys a good accuracy and a short computing time, which can meet the need for optimal design in effectively increasing the uniformity．