Abstract: This paper presents a 3-D current numerical model for the Yangtze River estuary with baroclinic-diagnosis mode in vertical σcoordinate system.A vertical eddy-viscosity coefficient is obtained from the advanced k-kl turbulence closure model, and the density baroclinic effects are embodied by the 2-D invariable-uneven salinity field.It shows the results from baroclinic-diagnosis mode well consistent with reality.The transition feature from back and forth current to rotary current is re-acted successfully.In addition,several tidal junction points appeare near branch points when tidal wave propagate from four river forks, the position of which change with runoff,tide and topography.