Based on the ship data of a certain port in China within one year, this paper analyzes the distribution characteristics of ship arrival time interval of the port within one year by using mathematical statistics method, and the Matlab tool is used to fit the three probability distributions of arrival probability of each ship type to obtain the goodness of fit, sum variance and root mean square difference. Through the analysis of fitting data results of negative exponential distribution, Weibull distribution and Erlang distribution, it can be compared and concluded that: when ship types are not distinguished, the arrival laws of all ships obey the Weibull distribution; When the ship types are distinguishes, container ships, bulk carriers and general cargo ships obey the Weibull distribution, while oil tanker arrival law obeys both the Weibull distribution and the low-order Erlang distribution.