Abstract: Based on the measured data of wind direction in the radar and through comparing the fit goodness in the fitted curve and regression analysis,it is proved that the Lorentz distribution function can be used to describe the distribution of the variation of the winddirection angle.The results show that the Lorentz distribution is more consistent with the distribution law of wind direction angle variation than that of Gauss distribution.The probability density distribution of the wind-direction angle variation described by Lorentz distribution is essentially same as with the fit goodness of Logistic distribution.Basis of that,the Lorentz probability density function of the wind direction angle variation is obtained.The characteristic angle in the Lorentz probability density function is a key parameter to determine the shape of the function which is correspond to the sampling time.Finally,the function relationship between the characteristic angle and the sampling time is obtained.