The invention relates to a process of an electroforming hard gold product. The process comprises the following steps of version design, rubber mold forming, wax injection, wax trimming, conducting oil feeding, gold casting, wax removal and conducting layer removal, and is characterized in that gold casting liquid in the gold casting step is prepared from the following ingredients including gold ammonium sulfite, ammonium citrate, phosphate, sulfate and complex ions of copper; according to the process conditions, the temperature is 45 to 65 DEG C; the PH value is 6.5 to 8.5; the current value is 0.015 to 0.02 A/g; the time is 24 to 32h. The gold casting liquid of the process uses gold ammonium sulfite as main gold salts; the ammonium citrate is used as a stabilizing agent; phosphate and sulfate are used as conducting salts; the complex ions of copper are used as crystal refiner, so that the monovalent gold ions formed by the gold ammonium sulfite and the ammonium citrate form fine crystals; the size of the crystal bodies of the fine crystals becomes large, so that the hardness of the gold product obtained through electroforming is also high.