The invention discloses a hard alloy surface carburizing method. The hard alloy surface carburizing method is characterized in that firstly, the temperature is kept at 550-700 DEG C for 1-2 h, so that a hard alloy green body containing a carbide forming element is formed; core/shell structure powder with Al2O3 covering TiH2 and graphene are mixed at the weight percentage ratio of 2:3 to be prepared into a hydrogenous carburizing medium, wherein the thickness of the graphene is smaller than 3 nm, the number of layers of the graphene is smaller than three, and the specific surface area of the graphene is larger than 250 m<2>/g; the green body is embedded into the hydrogenous carburizing medium and is compacted at the pressure of 5-15 MPa; and finally, liquid-phase sintering is conducted, and hard alloy surface carburization is achieved. The hard alloy surface carburizing method solves the problems that in the prior art, grains grow severely, the carburizing time is long, and efficiency is low, and hard alloy surface carburization is achieved in the sintering process.