A scanning error correction method is proposed to eliminate phase errors in white light scanning interferometry, addressing the limited measurement accuracy caused by inexact phase shift. Adding a monochromatic light interference signal detection device to a white light scanning interferometer allows the collected monochromatic signal to share the same phase error as the white light signal. The phase error obtained from the monochromatic light interference signal was used to correct the white light signal. The effectiveness of the scanning error correction method was verified through simulations and experiments on the roughness of a measurement surface and the repeatability of multiple measurements. This method further improves measurement accuracy based on the wavenumber domain phase compensation method proposed by our research group and enables the white light interferometer to adapt to noisy working environments.