Abstract: Copper-nickel alloys are widely adopted in seawater pipeline system of ships, which plays a crucial role in ensuring the normal operation of marine power plants, auxiliary machinery, and related equipment. To investigate the differences in corrosion behavior of copper-nickel alloy pipes from different sources, this paper developed an in-situ characterization method for corrosion behavior based on white light interferometry(WLI). This method gradually improved the measurement accuracy through steps such as screening test parameters and unifying the reference plane. The measurement results were verified by the converted values of weight loss method and the results btained by focused ion beam(FIB) cross-section method, ultimately realizing the precise measurement of corrosion morphology, corrosion thickness loss, and corrosion product film thickness. By applying this method to analyze the corrosion behavior of B10 copper-nickel alloy pipes, the main factors affecting the corrosion resistance of three different types of B10 copper-nickel alloy were identified. The results showed that the in-situ characterization method based on FIB established in this study could accurately characterize corrosion heights of 0.2 μm and above. Combined with characterization methods like FIB, it provides a new approach for evaluating the corrosion behavior of B10 copper-nickel alloy pipes.