In this study, the upper ocean temperature and salinity responses to typhoon Bavi (2008) were investigated using multiple remote sensing data, Argo data and HYCOM (Hybrid Coordinated Ocean Model) reanalysis data. The results show that: Ekman pumping near the typhoon center causes Upwelling, the seawater below the surface converges with high salinity cold water and turns upward, the Ekman transport direction points from the typhoon path to the coasts on both sides of the path, and the seawater accumulates on both sides of the Yellow Sea and causes downwelling. This leads to a decrease in SST (Sea Surface Temperature) and SSH (Sea Surface Height) near the typhoon path, an increase in SSS (Sea Surface Salinity), an increase in SSH along both sides of the path, and an increase in subsurface seawater temperature and salinity. In addition, due to the higher wind speed on the right side of the typhoon's heading direction, the intensity of Ekman transport on the right side is greater than on the left side. As the typhoon is closer to the land on the right side, the terrain blocks the wind speed, and the 10 m wind above the sea area on the southwest side of Jeju Island shows an Anticyclone rotation, with a negative EPV (Ekman Pumping Velocity), which is a downwelling. Therefore, there is a transition from strong Upwelling to downwelling in the sea area between the typhoon and Jeju Island. This will further strengthen the strong entrainment and vertical mixing on the right side of the typhoon's heading direction. This leads to a more significant decrease in SST and an increase in SSS on the right side of the typhoon's heading direction. In addition to entrainment and vertical mixing, the increase in SSS on the right side of the typhoon's forward direction is also related to the horizontal flow of surface seawater from south to north.