The work aims to improve corrosion resistance of cobaltrod, which is used to prepare Co-60 radioactive source, in high temperature air. Firstly, cobalt-nickel alloy was electroplated on the cobalt rod, and then nickel was electroplated. Finally, it was calcined in 600 ℃ mixed hydrogen and argon gas for 30 days. Corrosion resistance of the coating was analyzed by means of electrochemical method. The structure, composition and morphology changes before and after corrosion were studied by XRD, EDS and SEM. Optimal electroplating process conditions of Co-Ni alloy obtained from orthogonal experiment were: current density of 55 mA/cm2, solution temperature of 65 ℃, pH value of 4.0 and electroplating time of 25 min. Tafel curves, anodic polarization curves and AC impedance were tested with 3.5% NaCl solution at 30 ℃ as corrosive medium. Studies showed that Co-Ni alloy coating was present, which has increased the corrosion resistance of Co rod significantly. XRD test showed that the calcination of nickel coating did not change face-centered cubic structure. EDS test showed that nickel mass fraction accounted for 89.71% of the Co-Ni alloy coating. SEM indicated that morphology of pure cobalt changed dramatically after corrosion while that of Co-Ni alloy changed slightly after corrosion. The Co-Ni alloy coating between cobalt and nickel can enhance the adhesion of nickel to cobalt rod and its corrosion resistance at high temperature.