The invention discloses a mechanical downhole torque separation and transmission tool. The mechanical downhole torque separation and transmission tool comprises an outer shell, an upper dividing clawcylinder, a telescoping rotation cylinder, a dividing cooperation claw cylinder, a lower dividing claw cylinder and a rotary clutch connector. The upper dividing claw cylinder and the lower dividing claw cylinder are fixedly connected with the outer shell, the telescoping rotation cylinder is sleeved with the upper dividing claw cylinder and the lower dividing claw cylinder, and the tail end of the telescoping rotation cylinder is connected with the outer shell or the upper dividing claw cylinder through an elastic mechanism. The dividing cooperation claw cylinder is arranged in the middle ofthe outer wall of the telescoping rotation cylinder. The rotary clutch connector is connected with the outer shell through cooperation of an inverted curved stepped shaft and a ball. The mechanical downhole torque separation and transmission tool has the advantages that torque separation is conducted by using the tool, rotary directional drilling of a drill string is achieved, the tool can replacea rotary guide drilling system, and the mechanical downhole torque separation and transmission tool is lower in cost and higher in reliability; a new low-cost efficient drilling technology is formed,so that the technical drilling problems of a complex structural well are solved that the drilling string friction drag is high, the backing pressure is serious, the mechanical drilling speed is low,and the ultimate extension capacity is low.