The effect of cerium ions on the corrosion behavior of Zn-Ni alloy coating which electrodeposited on the Q235 steel surface by adding cerium salt in the electrolytes was investigated. The corrosion behavior of Zn-Ni alloy coating in 3.50%NaCl solution at 30℃ was studied by steady-state anodic polarization curves and Tafel curves and AC impedance methods. At the same time, the change of microstructure and apparent morphology of Zn-Ni alloy coating before and after corrosion were contrasted. The results indicated that crystal preferred orientation unchanged before and after corrosion, but the crystal texture coefficient of coating was changed after adding cerium salt, simultaneously the ipp and ip of Zn-Ni alloy coating reduced evidently, Rp increased obviously. When 0.80g/L cerium salt was added into the electrolytes, the crystal of coating became small and compact. This made corrosion resistance of the Zn-Ni alloy coating increase observably.