Abstract: By analysis on ground heavy fog occurred in Hainan province in 2012，this research study the making，principle and mechanism of V-3 structure model and blow-up concept model focus to the gap of the present forecast work and analyze the mesoscale disastrous weather.Some comparison of forecast，techniques will be made by the example of a advection-radiation fog.The analysis demonstrates that：①Analysis of weather situation plays an important part in forecasting disastrous fogs.②By example analysis，for disastrous fog，wind is southeast in 850925hPa north on the ground.Multiparameter structure information such as evolution makes a good effort for forecasting disastrous fog.③Fog has much to do with atmospheric stratification,and take a good correspond with the weather and visibility during fog.