Abstract: Using MIKE21HD hydrodynamic module to simulate the tidal and current field surrounding Fujian Dongwu bay,the computed tidal level,current velocity and direction are validated by comparing with the observed data.Consequently,it shows that the numerical simulation results agree well with the observed data.This tidal current numerical model reflects the local hydrodynamic conditions and it can be used as a base hydrodynamic data for the oil spill model.The oil spill module is based on Eulerian-Lagrangian "oil particle" method,considering the diffusion,drift and weathering process of oil film in the process of movement.We established a two-dimensional oil spill diffusion model arround Guanmen Fishing Port,simulating differentoil spillsituations in the moments of tidal(high water stand,low water stand,fastest flood and fastest ebb).Meanwhile,different wind regime (clam wind,summer monsoon,and winter monsoon) is considered,the different drift path,drift distance and swept area in different situations are analyzed.As a result,the drift and diffusion of oil spill near Guanmen is mainly affected by tide and wind,wind plays a key role in it.The maximum swept area and drift distance within 24 hours both occur in the situation that oil is spilled at ebb moment under clam wind,respectively as 6.66 km² and 17.63 km.Under the situation that oil is spilled at ebb moment under winter monsoon,the spilled oil will arrive at Maitreya bay on the southwest of Dong'an Island.In other situations,it moves back and forth along with the tide near Guanmen Channel.