Abstract: The eddy current testing method for the thickness of nickel-zinc composite coating on the surface of a uranium alloy bar was studied. Through theoretical analysis and experiments, a test device was established, the technological parameters of eddy current inspection were determined, the comparison samples were developed, and the inspection accuracy was verified. The detection results of samples in the normal production stage show that the detection accuracy of this method reaches 1 μm for samples with a Ni/Zn coating thickness of 4-15 μm.