In order to improve the measurement precision of ballistic trajectory, station distribution is taken as optimization object in this paper. Beginning with the observation equation of Photo-electric theodolite, the target function is constructed based on error propagation theory, which considers all the constraint conditions of engineering application: the capability of the optical measuring equipment, the angle between the optical measuring equipment and the sun, and the rules for the area selection. A distribution optimization algorithm on the basis of genetic arithmetic is proposed based on the target function. At last, the simulation experiments are presented, and the experiment results prove that the optimization algorithm can be applied to improve the precision of the measurement of ballistic trajectory.