The invention discloses a coplane unit of an electromagnetic valve deck machining device. The coplane unit of the electromagnetic valve deck machining device comprises a guide rail fixing frame. An air cylinder fixing base is arranged on the side face of the guide rail fixing frame. A coplane push-pull air cylinder is arranged on the air cylinder fixing base. A piston rod of the coplane push-pull air cylinder is provided with a coplane connecting plate. Fixing blocks are symmetrically arranged on the inner side face of the coplane connecting plate. The two fixing blocks are attached to the upper end face and the lower end face of the guide rail fixing frame. Wedge-shaped blocks are arranged on the side faces of the two fixing blocks. A coplane linear guide rail is arranged on the side face of the guide rail fixing frame. A sliding block on the coplane linear guide rail and the inner side of the coplane connecting plate are fixed. The sliding block on the coplane linear guide rail and the coplane push-pull air cylinder are the same in moving direction. By means of the above manner, the coplane unit is simple in structure, easy and convenient to operate and capable of making two planes be coplanar.