In order to study the dynamic response characteristics of gas-bearing coal and rock under impact load and the influence of gas pressure on the mechanical properties of coal and rock， triaxial impact tests of coal and rock under 0.25 MPa， 0.5 MPa， 0.75 MPa， 1.0 MPa， 1.25 MPa and 1.5 MPa gas pressure were designed in the laboratory. The results showed that the stress-strain curves of coal and rock under impact load took a trend of "steep increase-gentle-steep increase-yield-drop", which was related to the physical properties of coal and rock under impact load; with the increase of gas pressure，the strength of coal and rock decreases continuously， and the impact load carrying capacity of coal and rock under six different gas pressures was 132.11， 106.73 and 101.29 respectively. The failure strain of coal and rock under impact load decreased gradually with the gas pressure，and there was a linear decreasing relationship between them.