给出了在开放的Ｖ型三能级系统中的无粒子数反转激光理论。定态增益分析表明，在一定的条件下，无粒子数反转激光能够实现而不需要一个附加的泵浦场存在，而这个泵浦场在一个普通的封闭Ｖ型三能级系统中实现无粒子数反转激光是必不可少的。图示并分析了系统增益对驱动场和其他参量的依赖性。 The particle-free inversion laser theory in an open V-type three-level system is given. The steady-state gain analysis shows that under certain conditions, the particle-free inversion laser can be realized without an additional pumping field and the pump field can be realized in a normal closed V-type three-level system Particle inversion laser is essential. The dependency of the system gain on the drive field and other parameters is illustrated and analyzed.