In order to calculate the passing capacity of inland waterway preerably,the concept of gap rate and improves the gap acceptance theory’s model is proposed which considers that ship length is large and not all the bow can be used for the ship to move through.At the same time,it summarizes the rules of collision avoidance at slack water area and determines the three priorities of anisotropic traffic flow of the T-type intersection.Taking into account the influence of impedance effect of high level flow,the calculation method of T-type intersection traffic flow based on the priority is derived. Taking the T-type intersection of Sushenneigang waterway-Shenzhang waterway as an example,the analysis indicates that passing capacity gradually decreases with the increase of conflict traffic and the decreasing trend is the negative exponential distribution.When the conflict traffic is fixed,the passing capacity gradually increases with the increase of speed and the changing trend is slow-fast-slow.Therefore,it is reasonable to calculate passing capacity using avarage speed(eighty percent design speed).