Pan, P., 2019. Research and design of marine underwater LED illumination system based on sliding mode variable structure. In: Li, L.; Wan, X., and Huang, X. (eds.), Recent Developments in Practices and Research on Coastal Regions: Transportation, Environment and Economy. Journal of Coastal Research, Special Issue No. 98, pp. 239–242. Coconut Creek (Florida), ISSN 0749-0208.This paper introduces the working characteristics of an underwater LED illumination system and analyzes the driving power supply of the LED illumination system and the application of its control mode. In addition, the sliding mode variable structure control (SMVSC) method of constant-current power supply for an underwater LED illumination system is studied and designed in this paper. By choosing appropriate sliding mode surface function and control parameters, the constant-current control of the LED load is realized. Finally, to verify the effectiveness and superiority of the SMVSC method design for the LED illumination system, the SMVSC method is modeled and simulated using MATLAB software and compared with the conventional PI control method, which proves the validity of the design.