Abstract: Using the gas-liquid-solid three-phase displacement simulation system,a series of laboratory experiments on coal sample plugging and coal blockage removal driven by reverse water and gas injection the was carried out,the variation characteristics of coal sample permeability under different blockage pressures and blockage removal medium.pressures were discussed.The results show that the permeability of liquid phase decreases logarithmically with time in the process of coal sample blockage.The time to reach equilibrium tends to decrease with the increase of plugging pressure.The deposition of pulverized coal particles at the inlet of seepage blocks the pore and fracture channels of coal samples,which is the main reason for the decrease of permeability of coal samples.When the unplugging medium is water,the reverse water injection pressure is equal to the blockage pressure,the final liquid permeability of the coal sample is lower than that before the plugging. The reverse water injection pressure is greater than the plugging pressure,the liquid permeability will increase slightly in a certain period of time. Moreover,the higher the reverse water injection pressure is,the faster the reaction speed of the liquid permeability rises,and the final liquid permeability of the coal sample is equivalent to the value after the completion of plugging.When the unplugging medium is gas. The reverse gas injection pressure is greater than or equal to the plugging pressure,it can completely remove the blockages in coal sample.The variation curve of gas permeability of coal sample is similar to S\" curve,and the gas permeability in the whole process has experienced linear growth stage,exponential growth stage and stable stage.The output of a few small particle size and low density suspended pulverized coal particles promote the slow increase of gas permeability.The output of subsidence particles with relatively large density is the main reason for the coal sample completely removing the blockages quickly.The higher reverse gas injection pressure,the faster blockage removal speed and the closer the reverse gas injection pressure is to the plugging pressure,the more sensitive the plugging velocity is to the pressure change.The blockage removal ability of reverse gas injection is better than that of reverse water injection.The difference of water and gas molecular properties and drive rate is the main reason for the difference of reverse water and gas injection results.