Abstract: In order to improve the design efficiency and the heat flux uniformity of the infrared lamp array used for the spacecraft thermal test, this paper proposes an automatic optimization method for the optimal design of the infrared lamp array arrangement based on an improved particle swarm algorithm, with a heat flux distribution database for a single lamp and an automatic optimization design method for the array position parameters. Through reselecting the optimization parameters and set constraints among them, the traditional particle swarm optimization algorithm is improved to enhance the design efficiency. It is shown that compared to the genetic algorithm, the enhanced particle swarm algorithm is highly effective in accelerating the optimization process for the design of the infrared lamp array, with a time reduction of 82%, and a heat flux uniformity reduction of only 0.77%.