The invention discloses a hot rolling method for preparing a 21-10Mn7Mo welding wire, belongs to the technical field of welding, relates to preparation of solid welding wires of gas-shielded arc welding, relates to a hot rolling process of welding wires, and further relates to a forging stock and forging of the forging stock. A hot rolled wire rod is prepared from the following chemical components in mass percent: less than or equal to 0.10% of carbon C, less than or equal to 0.8% of silicon Si, 5.5-8.0% of manganese Mn, less than or equal to 0.030% of phosphorus P, less than or equal to 0.020% of sulphur S, 9.0-11.0% of nickel Ni, 19.0-22.0% of chrome Cr, and 0.5-2.0% of molybdenum Mo; and the ratio of Mn to Mo is controlled to be 7-7.5. Forging for preparing the forging stock comprises a step of blank heating; and the forging temperature is controlled to be higher than or equal to 1180 DEG C as initial forging temperature and high than or equal to 850 DEG C as final forging temperature. According to the hot rolling method of the hot rolled wire rod, preheating temperature in the heating step is controlled to be 650-750 DEG C.