In order to make the anti-tank missile attack the target at a larger impact angle, to improving missile damage efficiency, A new proportional navigation method combining angle constraint and overload constraint is proposed. First, setting up the prediction model of impact angle, obtain the factors that affect the impact angle: Then, the range of proportional coefficients is calculated with missile overload constraint: Finally, the prediction model is combined with appropriate proportional coefficient, obtain the initial value that satisfies the tactical index, and realize the missile hitting the target at a larger angle of attack. The simulation results show the correctness of the design method.