Abstract: The eddy current array and water immersion ultrasonic testing system were used to test the copper-coated steel sheet. Two methods are used for comparative experiments and the results show that both of them can achieve two-dimensional imaging of coating quality of this material. But a comprehensive comparative analysis has shown that results by eddy current array testing are better than that of ultrasonic testing, with the image of the former one being clearer and more reliable, and the signal-to-noise ratio being higher, which is consistent with the actual quality of the surface coating of the product. The results show that the eddy current testing technology has a good effect on the quality imaging detection and performance characterization of metal surface coatings.