Adopting LS-DYNA finite element simulation, the simulation model of hydraulic blasting was established. Numerical simulation of hydraulic blasting was carried out. Through the simulation, the point that the structure wall was affected by four loading functions, which include the first shock wave, bottom reflex compression wave, the compression wave of opposite wall and the bubble pulse, was put forward. The four loading functions help to extend the time span of loading, and provide basis for principle of quasi static pressure function of hydraulic blasting.