The invention relates to a square electromagnetic brake and clutch. The square electromagnetic brake and clutch comprises a chuck body and a cover plate, wherein coil slots are formed in the front side of the chuck body; entrance holes are formed in one side wall of the chuck body and communicated with the coil slots; a plurality of edge spring holes are further formed in the chuck body outside the coil slots; a center spring hole is formed in the center of each coil slot in the chuck body; a lower connection hole is formed in each of the four corners of the chuck body; a positioning pin unthreaded hole is formed at one side of each lower connection hole; an upper connection hole is formed in each of the four corners of the cover plate; a positioning pin threaded hole is formed at one side of each upper connection hole; coils are mounted in the coil slots; the end parts of the coils are led in from the entrance holes; springs are mounted in the edge spring holes and the center spring holes; the upper ends of the springs are propped against the lower surface of the cover plate; the cover plate and the chuck plate are integrally locked in the way that bolts sequentially penetrate the upper connection holes and the lower connection holes; positioning parts are arranged in the positioning pin unthreaded holes and the positioning pin threaded holes. The square electromagnetic brake and clutch has the advantages that the structure is simple, the precision is high and the disassembly and the assembly are convenient.