The invention discloses a coal seam gas well washing tool passing through a glass fiber reinforced plastics screen pipe. The coal seam gas well washing tool passing through the glass fiber reinforcedplastics screen pipe comprises a washpipe, a jet-flow vibration nozzle, a waterpower blocking type spraying nozzle, a pressure adjuster and a guide head. The washpipe is arranged at the center of theglass fiber reinforced plastics screen pipe. A first elastic centering sleeve is arranged between the washpipe and the glass fiber reinforced plastics screen pipe. The washpipe is sequentially connected with the jet-flow vibration nozzle, the waterpower blocking type spraying nozzle, the pressure adjuster and the guide head. According to the coal seam gas well washing of the screen pipe, due to alarge gap of the screen pipe, the flow speed of high pressure fluid released by the washing tool lowers after the high pressure fluid passes through the screen pipe, and therefore corresponding washing effect can not be achieved. During the cleaning process, fluid space can be shrunk and extruded by movement of a waterpower blocking ring and a movable pressing sleeve, and therefore the speed of the fluid flowing through the gas of the screen pipe increases, and cleaning effect is improved. In addition, the jet cleaning effect is improved by pressure pulse mechanism. A vibration cavity is formed in a nozzle mounting body, and the cleaning effect can be improved by pressure pulse generated by the vibration cavity.