By using wide scope ADCP data which were got during SCSMEX (South China Sea Monsoon Experiment) period in the summer of 1998, and comparing these data with numerical modelling result, the distribution and variation characteristics of the circulation and meso-scale eddies in the South China Sea (SCS) were studied. The results show that: (1) in the SCS, 18 different scale eddies or motion systems with characteristics similar to meso-scale eddy were found during the investigation; (2) a strong westward current was found in the south of the Taiwan Shoal; (3) the energy of those eddies west of 114°E was much stronger than that of the east;(4) and there exist many powerful meso-scale eddies in the Nansha region south of 12°N. The distributions of numerous eddies reflect the complexity of the circulation in the SCS. It seems that the formation of those eddies should be caused by joint work of wind, coast feature, bottom topography, water density, inertial force and continental shelf waves. By using wide scope ADCP data which were got during SCSMEX (South China Sea Monsoon Experiment) period in the summer of 1998, and comparing these data with numerical modeling result, the distribution and variation characteristics of the circulation and meso-scale eddies in the South The results show that: (1) in the SCS, 18 different scale eddies or motion systems with similar to meso-scale eddy were found during the investigation; (2) a strong westward current was found in the south of the Taiwan Shoal; (3) the energy of those eddies west of 114 ° E was much stronger than that of the east; (4) and there exist many powerful meso-scale eddies in the Nansha region south of 12 ° It seems that the formation of those eddies should be caused by joint work of wind, coast feature, bottom topography, water density, inertial force and continental shelf waves.