本文提出一种计算弹丸飞出后炮膛流空过程的一元非定常特征线法。它可计算初速与口径变化范围很大的各种火炮之流空参数。介绍了特征线网以及气流参数(压力、密度、温度、速度)随距离x及时间t变化的ALGOL计算程序,并将全部程序附于文中。 In this paper, we propose a univariate unsteady feature-line method for calculating the cavity emptying process after the projectile has flown out. It calculates the flow empty parameters for various artillery guns with a wide range of muzzle velocities and caliber changes. The characteristic line network and ALGOL calculation program of airflow parameters (pressure, density, temperature, velocity) with distance x and time t are introduced, and the whole procedure is attached to the text.