Abstract: Air Turbulence is an important event on Lhasa route which impacts flight security. According to the 13 cases of turbulence on the Lhasa route reported between 10 to 11^th February, 2014. Inspecting the wind field's forecast capability for upper jet stream from the World Area Forecast System (WAFS) data. Analysis the forecast effect and application of the newly clear air turbulence (CAT) grids data. The result manifests that:wind data from WAFS has higher forecast ability for clear air turbulence. It is better for the maximum CAT forecasting than the mean CAT, We can choose a number "4" as a threshold to draw turbulence forecast area on the Lhasa route, and amendment for using in applications.