The invention relates to an orthogonal flow regulation damping cylinder for an intelligent knee joint. The orthogonal flow regulation damping cylinder comprises a cylinder body and a hollow piston. One end of the cylinder body is in threaded connection with an upper cover, and the other end of the cylinder body is connected with a spring shell. The hollow piston is mounted in the cylinder body, the front end of a piston rod of the hollow piston is in contact connection with a stretching assistance spring in the spring shell, a spiral valve is mounted in the hollow piston, the side wall of the hollow piston is provided with an orthogonal flow passage, and a check valve is arranged in the orthogonal flow passage. By rotation of the spiral valve, flow areas of hydraulic oil passages of left and right cavities of the damping cylinder are changed successively to further change flow rate of the left and right cavities of the damping cylinder. The orthogonal flow regulation damping cylinder has the advantage that two-way independent control of bending and stretching damping of the artificial knee joint can be realized by the aid of one motor.