The rapidity and accuracy of the initial alignment influence the performance of the strapdown inertial navigation system (SINS), compass alignment is one of the most important methods for initial alignment. The selection of the parameters of the compass alignment loop directly affects the result of alignment. Nevertheless, the optimal parameters of the compass loop of different SINS are also different. Tradi-tionally, the alignment parameters are determined by experience and trial-and-error, thus it cannot ensure that the parameters are optimal. In this paper, the Genetic Algorithm-Particle Swarm Optimi-zation (GA-PSO) algorithm is proposed to optimize the compass alignment parameters so as to improve the performance of the initial alignment of strapdown gyrocompass. The experiment results showed that the GA-PSO algorithm can find out the optimal parameters of the compass alignment circuit quickly and accurately and proved the effectiveness of the proposed method.