The invention provides a GH4738 alloy as well as a homogenizing method thereof, a turbine disc fitting and a gas turbine, and relates to the metallurgical technical field. The GH4738 alloy homogenizing method comprises the following steps: slowly heating up a GH4738 alloy cast ingot, performing first-stage thermal insulation, upsetting, drawing out and performing second-stage thermal insulation, wherein slow heating refers to slowly increasing the furnace temperature to 1160-1200 DEG C from a temperature lower than or equal to 400 DEG C, and first-stage thermal insulation is performed at a temperature of 1160-1200 DEG C for 20-48 hours; during upsetting, deformation amount of the GH4738 alloy cast ingot is 10-30%; and the second-stage thermal insulation is performed for 40-60 hours at a temperature of 1180-1220 DEG C. The homogenizing method effectively eliminates main segregation elements of the cast ingot, saves energy, improves production efficiency, and solves the problems such asuneven crystalline grain structure and poor performance stability caused by alloy micro-segregation.