Abstract: Taiwan Strait has an unique geographical location, and the bay-island system in the western sea area is generally developed, which significantly affects the current field distribution of sea area. At the same time, the rapid development of the economic zone on the west coast of Taiwan Strait has put forward higher requirements for a deeper understanding of the background field of regional marine dynamic environment and its changes. Nanri Channel is the main waterway connecting Xinghua Bay and Pinghai Bay. In order to fully understand the annual changes of the background field of the regional marine dynamic environment under the influence of the bay-island system in the western side of Taiwan Strait, using statistical analysis, harmonic analysis, filtering and wavelet analysis, we studied the seasonal variations and driving mechanisms of coastal currents in Putian in the west side of Taiwan Strait, and preliminarily discussed the impact of extreme weather on the hydrodynamic evolution process. Results show that the tidal current in the study area is irregular semi-diurnal shallow water current, and the measured current has an obvious semi monthly periodic change. The flood tide velocity is larger than the ebb tide, and the main direction of the flood tide is WNW, the ebb tide is SE-ESE. The results of rotation spectrum show that the study area is under the influence of the semi-diurnal tidal energy with the counterclockwise energy stronger than clockwise, and there is no obvious spectral peak in the inertia period. The seasonal variations of tidal intensity are ranked as winter, spring and autumn, and then summer. The residual current velocities in summer and autumn are larger than those in other seasons and the surface residual current has obvious seasonal characteristics. The main WSW direction in spring, the NE direction in summer and the W directions in autumn and winter. The residual current flows northwardly throughout the year, showing obvious compensation flow properties at the bottom. The observed residual current is mainly caused by wind, and the magnitude of tidal residual current is very small compared with the surface and the correlations between them are significant. The wavelet energy spectrum shows that there is a good correspondence between the wind and current. The enhancement of 1d and 6 d periodic signals may be related to the typhoon transitions in summer. Results of this paper have important practical significance for regional marine environmental protection and marine scientific development and application.