The invention discloses a silicon carbide wafer bevel grinding, milling and polishing machine and an operation method thereof. The silicon carbide wafer bevel grinding, milling and polishing machine comprises a supporting sheet (1), a rotating shaft (2), a driving motor (3), a motor bracket (4), a vertical rotating arm (5), a horizontal rotating arm (6), a slide frame (7) and a screw rod (9) which are sequentially connected, wherein the lower end of the screw rod (9) is sequentially connected with a first cone gear (12), a second cone gear (13), an adjusting shaft (14) and a rotating wheel (15); a machining tool (19) of a silicon carbide wafer is arranged below the supporting sheet (1). The silicon carbide wafer bevel grinding, milling and polishing machine is reasonable in structural design, convenient to operate and high in working efficiency, bevel grinding, milling and polishing integrated machining can be performed on the silicon carbide wafer, the working efficiency is high, the roughness of a polished bevel can be smaller than 0.1 micron, the machining precision is high, and the applicability is high. The operation method can be applied to the bevel grinding, milling and polishing integrated machining on the silicon carbide wafer which is round or not round.