The work aims to determine the best preparation process parameter of the conductive ink by measuring the resistivity of conductive coating. Taking copper acetate as precursor, N,N-Dimethylethanolamine as complexing agent, and formic acid as reductant, the copper-based particle-free conductive ink of high conductivity was prepared. Copper-based particle-free conductive ink was prepared in chemical reduction method. The influence of the sintered temperature and time, and the ratio of Cu2+∶H+∶NH4+ on the coating conductivity was studied through orthogonal experiment to determine the best preparation process. The copper-based particle-free conductive ink with the optimal mole ratio of Cu2+∶H+∶NH4+ in the ink of 1∶3∶3 was stable in weak alkaline. The ink with optimal formula possessed high stability and conductivity. With the ink dropped and applied on the glass substrate to be cured for 30 min at 160 ℃, the coating resistivity obtained was only 0.18 μΩ•m. In conclusion, the low-temperature sintering of copper-based particle-free conductive ink is primarily achieved.