According to the fluid dynamics theory, the kill rate has an important effect on the fluid friction. So in order to calculate the kill rate of empty well control, the kill rate's effect based on previous models is considered, the quasi-transient model of rescue well killing in empty wells is improved, and a mathematical computing software is used to calculate the kill rate. The numerical calculation results show that: the kill rate has a negative relation with the density of kill fluidand the depth of the well, but has a positive relation with the size of boreholes. The validation's error is controled with in 1%, indicating that the calculation method can achieve the field accuracy requirements, so subsequent similar wells killing can get certain guidance from this study.