Abstract: In this paper, the Global Ionospheric Scintillation Model （GISM） has been introduced.Comparison between the model predictions with observations over Hainan region has been made using one year＇s data. The results show a good overall agreement between GISM predictions and observations in seasonal variation, diurnal variation and spatial distribution. In seasonal variation, GISM predictions agree in general with observations at moderate scintillation level, but there is more deviation at weak or strong scintillation levels. In diurnal variation, GISM predictions accord with observations on the whole, except for a delay of about one hour in the occurrence maximum. In spatial distribution, both observations and predictions show that occurrence in the south of Hainan is higher than that in the north.