Three-parameter Weibull distribution has obvious advantages in fitting the life of LED lamps, but it is not easy to obtain more accurate point estimations of three-parameter Weibull distribution. At present, the commonly used parameter estimation methods, such as maximum likelihood method, moment estimation method, Bayes estimation method, etc., have complex equations, which makes the software programming very troublesome and difficult to master, and the parameter estimations may not be obtained. In view of this, a simple method to estimate the parameters of three-parameter Weibull distribution is proposed for the constant stress accelerated test in this paper. This method does not involve the solution of transcendental equation so that the software programming is quite simple, and the statistical idea is clear. The application of the method is illustrated by several case data of LED lamps under constant stress accelerated test, and the comparative analysis is made with the existing methods. It can be seen that the proposed method has significant advantages.