本文主要介绍用有限差分法计算一种带有尾翼的特殊弹丸在有攻角时三维绕流流动，通过求解三维 Ｎ Ｓ方程得到流场流动参数，并通过对物面处压力和应力的积分，得到弹丸诸气动力系数．其计算结果可供设计人员参考． In this paper, the finite difference method is used to calculate the three-dimensional flow around a special projectile with tail at the angle of attack. The three-dimensional NS equation is used to obtain the flow field parameters. Through the integration of pressure and stress , Get the projectile various aerodynamic coefficient. The calculation results for designers reference.