Abstract: Weibull distribution is of great fitting precision and good adaptability for maxmum wind speed, height of wave and precipitation. Four parameter estimate methods of Weibull distribution are given in this paper. They are probability weighted momented (PWM),least square method (LSM)、maxmum likelihood (M-L) and fitting (FIT) respectively. The results of statistical tests show that fitting precision of PWM,LSM and M-L methods is higher than others, and PWM method is the most convenient. The calculating processes in LSM and M-L methods are greatly simplified because of the assumption of parameter a0.The formula of experience accumulation frequency Pi=i-0.35/n(i=1,2,…,n) is better fit to Weibull distribution than others. The calculation precision using three parameters is much higher than that of using two parameters.