Abstract: Through research of single physical model for photovoltaic array, the paper gave a mathematical model of photovoltaic array easy to solve and simulate, which can calculate I-V characteristics of photovoltaic array at any temperature and solar radiation intensity. Based on the model, it also gave calculate formula at the maximum power point in allowable error of project. The Matlab simulation result of the mathematical model showed that output characteristics of the photovoltaic array vary with temperature and light intensity, moreover , I-V and P-V characteristics of the photovoltaic array is nonlinear; in different light intensities and temperatures, the output of the maximum power point is different , which can reflect actual characteristics of photovoltaic array.