本文计算了开口腔的雷达散射截面。利用几何光学法结合口径积分，从腔壁反射的射线遵循几何光学定律，并可应用于出射射线的后向散射中。这种方法概念简单，对腔的形状或者腔内壁的涂复材料没有限制。使用本方法计算了底部为理想导电板圆截面腔的雷达截面，与文献[4]值吻合很好。然后分析了类J82进气道的雷达截面，最后，讨论了该方法的局限性以及可能改进的方向。“,”An approach is presented for calculating the radar cross section (RCS) of a partial open cavity,The rays bounced from the cavity walls follow the law of geometrical optics, and is then applied to compute the backscattered field of the exit rays. This method is so simple in concept that there is virtually no restriction on the shape or plating material of the cavity. Numerical results obtained from this method are compared with those of a circular cylinder terminated by a PEC plate in the literature. Good agreement is obtained. RCS patterns for a S-band J82 inlet is computed. Finally ,some of the limitation and possible extensions of this technique are discussed.