In order to verify the maximum power point tracking algorithm and evaluate, simulate, and optimize photovoltaic system, the maximum power point needs to be detected. In this paper, a maximum power point detection method for photovoltaic (PV) module based on Lambert W function is presented to achieve the high-precision detection. By using piecewise curve-fitting method, a maximum power point detection and optimization algorithm based on Lambert W function is proposed. Meanwhile, the characteristics of the DC-DC converter used for detection are analyzed in detail, and the working conditions of the converter which can realize full range detection are obtained. Moreover, the performance of the proposed method is investigated by modeling, simulation, and experiment of PV system. Furthermore, errors and statistical analyses are carried out to illustrate the precision of the proposed method. The results validate the model well with experimental work. Compared with previous methods in other works, the results demonstrate the proposed method correctness and effectiveness.