Abstract. F2 (0.004), its prediction formula relies on inverse fuzzy numbers, the difference of historical data and the differential-difference of the historical data. F2 (0.004) is a fuzzy time-series forecasting model. This paper reports the application of F2 (0.004) on forecasting research about the historical data of tourist number in Sanya from 2006 to 2014 and the number of tourist in the unknown year 2015. For the study of time series forecasting problems, F2 (0.004) is an added new methods.