Accurate passenger-flow forecast has always been playing the crucial role on the construction and development of the airport. This passage based on the data of passenger flow from 2005 to 2015 at Sanya Phoenix International Airport is proposed to predict the flow from 2016 to 2017 by adopting Holt-Winter seasonal model, ARMA model and liner regression model. In order to promote the forecasting accuracy, the portfolio weight method is used to forecast the result and reduce the error. According to the verification, this measure is one of the effective ways to predict the passenger flow.