The invention discloses an adjustable plastic drilling device. The adjustable plastic drilling device comprises a box body, a drilling device and clamping devices, wherein the top of the box body is fixedly connected with a first motor through a machine frame, a first gear is fixedly arranged at the front end of an output shaft of the first motor, the first gear is meshed with a rack fixedly arranged at the top of the drilling device, the middles of the side walls at the two ends of the box body are rotationally connected with a first rotating shaft and a second rotating shaft in a rotating mode, and a first roller is fixedly installed on the surface of the first rotating shaft. The invention relates to the technical field of machining equipment. According to the adjustable plastic drilling device, a second motor is used for driving a second belt wheel to rotate, a belt is used for driving the first belt wheel to rotate, a semicircular gear is indirectly driven to rotate, the semicircular gear and the second gear are meshed intermittently, the conveying belt is intermittently conveyed, and the moving distance of the conveying belt is equal to the distance between positioning blockswhen the second gear rotates by one circle, so that each clamping device can be accurately stopped below the drilling device, and the machining precision is guaranteed.