In order to develop capability of precision guided munition, ballistic characteristics of two dimensional trajectory correction projectile with a pair of NACA airfoil based on 120 mm mortar projectiles were studied. First of all, based on establishment of the trajectory correction model, the aerodynamic coefficients of mortar projectiles under different operating conditions were calculated by using Fluent, and then two ways of proportional guidance law of gravity compensation to terminal guidance of the projectiles were introduced, and the trajectory simulation data under different proportional guidance was obtained, finally, the simulation results were analyzed. The results show that this kind of guided projectile has better trajectory correction ability, and utilization of proportional guidance with the over-gravity compensation could greatly reduce the overload, which can provide reference for the follow-up design of guided mortar projectiles.