To achieve the idea of speed and precise strike, firstly, establishes 6-DOF trajectory model to get a theory trajectory orbit which passes the target with the methods of Runge-Kutta and Adamas. Use Kalman filtering to get precise coordinate data of the flying projectile and calculate the deviation. Threshold function is led in to get the real trajectory orbit. The results show that the model can significantly deduce the complexity of projectile conversion and the hit deviation of projectiles.