In order to solve the problems that engineering model of photovoltaic array has low accuracy (within 5%) and five-parameter model has more parameters which are difficult to obtain, a new method of parameters extraction is presented in this paper. This method is first to use Lambert W function to obtain the analytic expression for photovoltaic module, then to use polynomial curve fitting method to obtain the current-voltage relationship of PV module, and finally to use the subsection integral method to obtain the value of parameters for photovoltaic module. The proposed method shows that the accuracy is within 0.5%. Compared with conductivity method and pattern search method, this method not only has intuitive features but also is easy to use. Furthermore, the obtained photovoltaic module parameters possess smaller errors (within 0.1%).