The invention discloses a gas and dust mixed explosion simulation testing device, and belongs to the field of researches on the prevention and control of coalmine disasters. The device consists of a methane gas bottle, a compressed air bottle, pressure reducing valves, electromagnetic valves, flow meters, a tee joint, a dust cavity, valves, a vacuum pump, a simulated roadway, a test rack, an explosion-proof safety valve, an ignition probe, an igniter, pressure sensors, temperature sensors, carbon monoxide sensors, a data acquirer, a high-speed camera, a triangular bracket, a computer, a connecting pipe, connecting lines, a data line and a dust sweeper. According to the device, researches on a mutual promotion relationship between gas explosion and dust explosion and evolution laws about each characteristic parameter of gas and dust mixed explosion can be made, and the device is significant for researches on the prevention and control of extra-serious coalmine disasters and accidents.