Abstract: The stability of time series and the fatality rate of 100,000 population of traffic accidents in Beijing are analyzed by ARIMA model.The ARIMA model forecasted by spss 11.5 software and it improved the pre- cision of the forecasting result.The ARIMA model is able to be used for all kinds of seasonal and non-seasonal time series in practice.The forecasting data obtained from the ARIMA model simulates the actual data well. The result is very important to the government for countermeasures making which help prevent traffic acci- dents from happening.