Large passenger flow on holidays often brings great pressure on urban rail operation and management. Timely and accurate prediction of passenger flow during holidays can provide an important basis for urban rail transit operation and management departments to formulate transportation plans and determine countermeasures, so as to ensure the safe and smooth operation of rail transit during holidays. Based on the analysis of the change trend of passenger flow in holidays, the paper obtains the benchmark passenger flow by historical passenger flow trend, and constructs arima-garch model based on the current passenger flow level to predict the passenger flow of rail transit in different periods of holidays in the future. Based on the historical passenger flow data of Suzhou rail transit in 2018 and 2019, the method is verified and analyzed. The results show that: the method can effectively identify the characteristics of passenger flow on holidays, reduce the preliminary work of passenger flow forecast, and realize the passenger flow forecast of urban rail transit in different periods of holidays.