Abstract: On the premise of ensuring the ultra-high vacuum system and performance index of the original X-ray photoelectron spectrometer (XPS). A synchronous illumination-XPS characterization system for photocharge separation and transfer of semiconductor photocatalysis has been designed and developed. By combining XPS and the semiconductor photocatalytic system, the synchronous illumination of the external light source and X-ray surface of the semiconductor was realized, the binding energy data of characteristic elements before and after light irradiation were observed and recorded. The result infered the interface atomic photocharge separation and migration process over photocatalyst.