For evaluating the certain type projectiles launching safety, dynamic analysis model of the kinetic energy projectile was established based on the nonlinear finite element method. The simulation results were validated by comparing and analyzing with the experimental data. Then, based on the above analysis model, the influences of projectile mass eccentricity, the gap during sliding-block and rails, thrust eccentricity on the transverse acceleration were studied. The simulation results indicates that the launching safety decreasing when transverse acceleration of the projectiles increasing with the mass eccentricity and thrust eccentricity, and the launching safety decreasing when projectiles collision increasing with decreasing the gap during sliding-block and rails.