The reliability of planetary gear transmission is mainly determined by load-sharing characteristics between the planetary wheels. The study on the load-sharing characteristics of planetary gear train is carried out based on the nonlinear finite element method. Taking the controlled start transmission（ CST） planetary gear transmission part used for scraper conveyors as study object,the dynamics simulation of the planetary transmission is carried out by ANSYS/LS-DYNA. The curves of dynamic contact force and the frequency spectrum of each meshing pair are obtained. The influences of load-sharing measures,impact load,inertia load,rotating speed and contact parameters on the load-sharing characteristics are analyzed. The contrast study show that both the center external gear and the planetary frame floating improves the system load characteristics remarkably. The impact load and speed increases make the load distribution between planetary wheels more uneven. The light of the planet carrier can make the load distribution among the planetary wheels more uniform.