To improve the simulation precision of Line of Sight of Laser Target Seeker (LSLTS), the source of the errors affecting the precision is analyzed according to the process of the simulation. The precision model of angel of LSLTS is constituted based on errors composition theory, and the evaluation criteria of the whole screen is established. On the basis of the criteria, the equipments layout of the laboratory is designed by applying the Genetic Algorithm (GA). The distribution of angel errors in the screen is achieved, which gives support to the design of the LSLTS simulation.