Cruise observations with CTDs (Conductivity-Temperature-Depth profiler) and a moored ADCP (Acoustic Doppler Current Profiler) were carried out on the continental shelf of southern East China Sea (ECS) in summer 2003. Analyses of the cruise data reveal a low temperature belt sandwiched by warm waters on the shallow water side and on the continental slope side. Within the belt there are three cold centers with horizontal scales of 30 to 100 km distributed as a chain from the southwest to the northeast. The upward protruding isotherms and ¿ -- spiral-like daily averaged horizontal velocity structure indicate that the northeast cold center has all features of a mesoscale cold core ring. Estimated vertical velocity is of the order of 5 ¿ 10-5 m s-1.