The invention provides a dynamic pressure-variable desorption experiment system for drilling cuttings. The dynamic pressure-variable desorption experiment system comprises a high-pressure gas source module, a vacuumizing module, a dynamic drilling cutting simulation module, a desorption-pressure-variable control module and a parameter acquisition, measurement and control module. Drilling cuttings in a container are disturbed through the dynamic drilling cutting module so that different movement states of drilling cuttings can be simulated when coal seam gas-bearing capacity is measured through underground coal mine compressed air sampling. The coal sample gas desorption environment pressure is regulated through the desorption-pressure-variable control module, and therefore a pressure-time function can be achieved when the desorption environment pressure is positive pressure, dynamic desorption characteristics of drilling cuttings under different movement states and different magnitudes of desorption environment pressure, and the true state of coal sample desorption is simulated when the coal seam gas-bearing capacity is measured through underground coal mine compressed air sampling. System measurement and control are sensitive, the desorption amount in seconds can be achieved, and the theoretical foundation is provided for perfecting a gas loss amount calculation module in the compressed air residue discharging and sampling process and improving the gas amount measurement precision.