In the field test of photovoltaic array, the output characteristics of PV array can not be obtained in a short time. Therefore we built a mathematical model of PV array based on the physical model of PV array. Then we established a simulation model in Simulink and done some optimization to prove the correctness of the model. On this basis, we designed a PV array simulator with MSP430 as the main control chip and Kingview as upper monitor software.We used kingview design man-machine interface so that we can find working point when we input diffierent light intensity, temperature and external conditions. We can control the output characteristics of the PV array simulator in different conditions by controlling the output voltage of the MSP430 chip.