Li, Z. Duan, Q.H. Gao, L. Han, Q. Ma, Y.X. Sheng, W.F. Yue, Z.Y. JACoW Publishing Geneva, Switzerland The fourth generation synchrotron radiation light source currently under construction in China has the characteristics of high energy and high brightness. High Energy Photon Source(HEPS) can be used in many basic and engineering research fields, so different spot sizes are modulated for different research needs. This design is a rotary water-cooled white beam slit system, which mainly includes absorber parts and driving mechanism. On the premise of ensuring the integrity of the absorber, the aperture is processed inside the absorber, and the absorber is rotated by the driving mechanism, so as to realize the adjustment of the aperture of the slit. The system has the characteristics of compact structure, high yield and simple processing, and can achieve the same performance index while saving time and space costs. At present, the function of the experimental prototype has been verified on the 3W1 high energy test beam line of BSRF, and the spot size can be adjusted.