Abstract: Gas containing rate is the key parameter that affects impact erosion capability of gas-liquid two-phase jet. We analyzed the relationship between impact force of gas-liquid two-phase jet and crushing depth of coal by the experiment research on different inlet pressure erosion performance of two phase flow. Research shows that the impact force size of gas-liquid two-phase jet is proportional to the crushing depth of coal and rock; the greater static pressure of gas-liquid two-phase jet in its impact zone is, the stronger its impact erosion capability is; when inlet pressure is 0.6 MPa, compared to the water jet, the average impact erosion capacity of gas-liquid two-phase jet can increase nearly 28%. Therefore, the gas-liquid two-phase jet can effectively improve jet rock breaking efficiency, reduce the operating pressure of system, and enhance the safety and reliability of system.