Due to the limitation by the natural terrain depth of the Yangtze River channel and navigable clearance of Nanjing Yangtze River bridge, the longitudinal extension and radiation of port logistics service are seriously held up. Thus the newly built port in the downstream of the Yangtze River shall be able to undertake the transshipment of vessels from the upstream to the sea and then to the river. The present code includes detailed stipulations on the width of the excavated-in basin, but there aren’t any stipulations yet on the entrance width of the excavated-in basin which is between two wharves. From the angle of navigation channels, drift angle and yaw angle, this paper focuses on the calculation and determination methods for the entrance width of excavated-in basin between two wharves.