The work aims to study the effect of the reducing agents like sodium hypophosphite (SHP) and hydroxyl sulfate (HAS) on immersion gold-plating, so as to solve the problems of corrosion and difficult deposition in late period of immersion gold-plating on Ni-P layer. The effects of reducing agents on stability of plating bath were studied by continuous heating test. The molecules of compounds were calculated by density functional theory, and the Fukui function and orbital energy level were compared before and after the reaction. Au thickness was tested by XRF, and the effects of reducing agents on plating thickness were analyzed in combination with open circuit potential (OCP). The effects of current transients on nucleation mechanism and growth of Au deposition were analyzed under constant potentials. Micro-topography of plating was characterized by SEM. Tafel test was used to analyze the electrochemical corrosion resistance of layers. The simultaneous addition of SHP and HAS did not affect the stability of plating bath, and the production of amidoxime groups reduced the reactivity of Au+. The thickness of Au layer exceeded 0.09 μm under 0.05 mol/L SHP and 0.03 mol/L HAS. Under the action of SHP, the precipitation of Ni in the gold plating process was reduced, and the corrosion of the Ni layer was effectively suppressed. The nucleation mode turned to instantaneous nucleation after the addition of HAS and the size of the Au grain became larger. The reduction of Ni corrosion and the increase in the thickness of Au layer greatly improved the corrosion resistance of the entire coating. The addition of SHP and HAS increases Au deposition rate and suppresses Ni corrosion, thus improving quality of Ni-Au layer, increasing industrial production efficiency and meeting the new requirements on high density and high frequency of PCB.