The invention in particular relates to a pneumatic extrusion type washing machine which directly applies pressure onto fiber tissues of clothes, imitates hand rubbing effect and does not damage the clothes. A working principle of the pneumatic extrusion type washing machine comprises that air pressure produced by an electric air pump is acted on inner wall of an air cylinder (205) fixed below an upper cover of washing machine under the control of an air suction and air exhaust change-over electromagnetic valve (203), and a piston rod (215) is pushed to extend or retract; the piston rod drivesa telescopic frame movable arm (208) connected with the piston rod, and actions that the telescopic frame stretches downward and is fixed or retracted to upper cover of washing machine are completed;when telescopic frame stretches and a plastic extrusion head (214) approaches a barrel head, the plastic extrusion head (214) compresses clothes (501), moisture inside fiber tissues of the clothes isextruded out, and stains, dissolved by moisture, on clothes and the moisture are discharged together from the interior of the fiber tissues; after an extrusion state is maintained for a period of time, the air suction and air exhaust change-over electromagnetic valve (203) of the air cylinder changes over, air suction and air exhaust directions are changed, the piston rod of the air cylinder is retracted, the telescopic frame is driven to be retracted, and the extrusion head is driven to go up; when the plastic extrusion head leaves the surface of the clothes, the telescopic frame stops retracting, and the moisture in the washing machine enters the interior of the fiber tissues of the clothes again; then the telescopic frame continuously stretches downward, the plastic extrusion head continuously applies pressure to the clothes, and the moisture in the clothes is extruded; and the process is continuously repeated, so that the aim of cleaning the clothes is achieved.