This study is made, considering that cadmium has various problems as an impurity in the electrowinning process of zinc, (1) to elucidate the behavior of zinc-cadmium electrodeposition depending upon the change of several fundamental factors of the process, (2) to observe the procedure of zinc-cadmium alloy electrodeposition with reference to the polarization curves, (3) to find out the mechanism of the formation of metallic hydroxide according to high pH value in the vicinity of the cathode, and finally (4) to make clear the mechanism of zinc-cadmium alloy deposition by measurement film resistance.