The invention discloses a process for manufacturing a hard alloy coating, which comprises the following steps of: 1) coarsening the surface of a workpiece basal body; 2) preheating the workpiece basal body, namely heating the workpiece basal body through electromagnetic induction, wherein the power of a power supply is 60 to 100 kw, the frequency is 2,000 to 10,000 Hz, an induction heater has 1 to 10 turns of coils, the temperature is between 150 and 360 DEG C after heating for 10 to 30 minutes; 3) spraying the hard alloy coating, namely spraying the hard alloy coating on the workpiece basal body, wherein the oxygen pressure is 0.1 to 0.5 MPa, the acetylene pressure is 0.01 to 0.05 MPa, the spraying distance is 150 to 230 mm, and the spraying temperature is between 250 and 300 DEG C; and 4) performing remelting, namely heating up a workpiece through the electromagnetic induction, wherein the power of the power supply is 60 to 100 kw, the frequency of the power supply is 2,000 to 10,000 Hz, the induction heater has 1 to 10 turns of the oils, and the workpiece is heated to the temperature of between 900 and 1,150 DEG C. By the process for manufacturing the hard alloy coating, a compact, high-hardness, high-abrasion and corrosion resistant hard alloy coating can be formed.