The invention provides a mechanical keyboard key structure and an installation method thereof, which relates to the technical field of the mechanical keyboard. The mechanical keyboard key structure comprises a balance bar connecting piece, a keyboard support and a key cap. The outer contour of the balance bar connector is cylindrical, the side wall of the balance bar connector is provided with anedge, the top wall of the balance bar connector is provided with a first cross structure, and the side wall of the balance bar connector is also provided with a through hole, which is used for inserting and connecting with the balance bar. When the user presses the corner or edge of the key cap, As the outer contour of the balance bar connector is cylindrical, and the force concentrating part of the balance bar connector is circular arc, the resistance of the balance bar connector can be reduced, so that the resistance of the corner or edge of the key cap pressed by the user is reduced, the key cap pressed more smoothly, and the comfort degree of the user pressed the key cap is improved.