The invention provides a single screw extruder, comprising a driving motor (4), a screw (12), a cylinder (13), a cylinder heating coil (14), a reducing gearbox (15) and a base (11); the driving motor (4) is connected with the reducing gearbox (15) which is connected with the screw (12) which is rotatablely matched in the central hole of the cylinder (13); the external surface of the cylinder (13) is provided with the cylinder heating coil (14); a lifting device and a rotation device are arranged between the cylinder (13) and the base (11). Compared with the prior art, the single screw extruder has the advantages of directly adjustable extruder body height, rotatablely adjustable extruder body within 360 DEG along the horizontal direction and the vertical direction, large applicable range, simple operation, small land occupying, and large adjusting range.