The utility model belongs to the technical field of colliery hydraulic support is with the dynamic behavior test of large -traffic relief valve, dynamic behavior in order to test large -traffic relief valve convenient, effectively provides a large -traffic relief valve test device, including being fixed in the pneumatic cylinder and explosion jar on the mounting bracket, the pneumatic cylinder is static relatively with the cylinder body of explosion jar, and the pneumatic cylinder is connected through same piston rod with the piston of explosion jar, is equipped with the enegy absorber along the mounting bracket of rod travel direction on, and the enegy absorber is less than hydraulic cylinder piston to the ultimate range of the cylinder body inside bottom of pneumatic cylinder to the first ultimate range of tailpiece of the piston rod of pneumatic cylinder side, closed chamber body coupling in the explosion jar has air intake system and exhaust system, and the upper and lower cavity of pneumatic cylinder is connected with a plurality of liquid ways respectively, and the cylinder body of pneumatic cylinder is equipped with by the installing port of examination relief valve with the department of connecting with of the cylinder bottom of pneumatic cylinder. The test device open quick, that pressure increases the gradient is high, the overall process of can fine simulation opening overflow, specified overflow and closing.