The invention discloses an experimental device for the coal and gas burst, comprising a coal sample chamber and an atmospheric pressure loading device, wherein the coal sample chamber is provided with coal and gas exhaust nozzles having control valves, the atmospheric pressure loading device is provided with an atmospheric pressure loading channel that communicates with the inside of the coal sample chamber having a diaphragm in front of the control valves, and a cavity between the diaphragm and the control valves is a balancing cavity connected with a balanced atmospheric pressure loading device; the device also comprises a pressure acquisition device in the coal sample chamber and a camera arranged outside the coal sample chamber and the part of the coal sample chamber opposite to the camera is transparent. The invention is capable of simulating the pressure of gas and physical force of coal, achieving the instant fast pressure release to be closer to the actual coal and gas burst and the damage process of coal, and observing and recording the simulation to provide the theoretical foundation of forecasting and preventing the coal and gas burst; during the use, the grain diameterof powdered coal, pressure while the formation and charging pressure can be regulated to observe the grain diameter parameters of different powdered coals and the experimental result under different pressures, and the device is flexible in use.