Abstract: In order to study the propagation law of shock wave of gas explosion, the simulation on the overpressure and transient velocity of shock wave has been carried out with AutoReaGas software. It was found that overpressure was separately divided into three stages, and transient velocity as the intuitive performance of gas movement was divided into four stages. The coupling relationship between overpressure and transient velocity was linear relationship. The prediction equation can be used to evaluate the transient velocity of shock wave under this research conditions.