The work aims to find out the optimal process conditions and figure out the mechanism of Zn-Ni electrodeposition. The effects of the mole ratio of zinc ions to nickel ions and the total molar concentration of zinc ions and nickel ions on the glossiness, nickel content, corrosion resistance, appearance quality and microstructure of the coating were studied in an alkaline electrolyte system with an amino-carboxyl polyfunctional ligand as Ni2+ chelant by means of field emission electron microscopy, energy spectrum analysis and electrochemical analysis. The nickel content of the coating decreased with the increase of mole ratio of zinc/nickel ions, and was finally stabilized between 15%~19% and the microstructure of the coating changed from fine and smooth crystalline grain to coarse and loose one. When the mole ratio was 1.9, the corrosion current of the coating dropped to the lowest. The increase of the total molar concentration of zinc and nickel ions led to a slow decrease in nickel content of the coating and the microstructure of the coating changed from fine and loose crystalline grain to fine and compact one, but finally to the coarse and loose one. The corrosion current of the coating firstly decreased and then increased sharply with the total molar concentration, indicating that the corrosion resistance of the coating firstly increased and then decreased sharply. When the mole ratio of Zn2+/Ni2+ is 1.9 and the total concentration of Zn2+ and Ni2+ is 0.12 mol/L, the comprehensive properties of the coating are the best. The changing trend of Zn/Ni content in the coating is consistent with the adsorption film theory of Brenner.