在正交曲线坐标系下 ,采用坐标变换、有限差分、交替隐式求解、动边界处理等方法 ,建立了边界拟合网格的三维潮流数学模型 .应用在长江口潮流场的计算中 ,得到了与长江口实测潮位、流速和流向相一致的结果 ,能较好地反映长江口复杂边界和地形下的三维潮流场变化 In the orthogonal curvilinear coordinate system, a three-dimensional tidal current mathematical model of boundary fitted grid is established by means of coordinate transformation, finite difference, alternating implicit solution, dynamic boundary treatment and so on. The results consistent with the measured tidal level, velocity and direction of the Yangtze Estuary can better reflect the changes of the tidal current field under the complicated boundary and topography of the Yangtze Estuary