In photoelectricity scanning system, stagnation zoon of thermal blooming makes energy of laser propagation decrease through atmosphere. The probability of stagnation of thermal blooming is decided by joint probability of wind speed and direction of atmosphere. Based on the wind profile radar one hour average wind field data from May 2007 to June 2011, according to the least square method, Frechet, Gumbel and Weibull probability distribution were fitted. The fitting parameters, correlation coefficient and residual standard deviation were obtained. The optimal model was achieved by the comparison of different results. In condition of no good fitting result of above method, based on sample data, according to the characteristics of circular normal probability distribution, zonal wind and meridional wind average value and mean square deviation can be calculated. The relationship of wind field probability varying with wind speed and direction can be obtained so as to obtain probability for some wind field.