Abstract: An 1.5 MW wind turbine gearbox is considered as the research object in this paper. The life distribution model of the turbine gearbox is obtained by building dynamic reliability models of mechanical components based on design parameters. The life distributions are assumed to follow Weibull distribution with two parameters and lognormal distribution, and the parameters estimation is conducted with the least square method. The correlation coefficient method is then used to testify the estimation results. The results show that the Weibull distribution fits the life data well.