The invention discloses a composite functional oil cylinder. The composite functional oil cylinder comprises a cylinder body with openings arranged at two ends, an upper end cover is fixedly installedat the opening of the upper end of the cylinder body, a lower end cover is fixedly installed at the opening of the lower end of the cylinder body, a piston body is slidably connected in the cylinderbody, and a piston rod penetrating through the upper end cover is arranged on the piston body; a rodless cavity is formed between the piston body and the lower end cover in the cylinder body, and a rod cavity is formed between the piston body and the upper end cover; a gas hole communicating with the rod cavity is formed in the side surface of the cylinder body, a piston hole is arranged at the lower end of the piston body, a piston ring is arranged at the lower end of the piston hole, a convex column is arranged at the lower end cover, an A port and a B port are arranged at the lower end of the lower end cover, a control valve is fixedly installed with the part, close to the outer circumference of the upper end, of the side face of the piston rod. The composite functional oil cylinder notonly is simple in structure, but also enables a pipeline of a system to be more concise through two oil ports, and the control is simpler to conduct switching of working conditions through pressure changing.