Abstract: A method of initialization for the planetary boundary layer was presented to numerical analysis of the structure of PBL jet stream. Based on the surface and 850 mb level data over the southern China, by using this method, the wind fields at 50,100,300,600,900,1200,1500 m levels are calculated. It is evident that these results are close to the observatio ns and may give a more fine description of the structure of PBL jet stream. Probably this method is applicable to numerical analysis for the PBL.