Abstract: In view of problems existed in common control methods of constant voltage method, disturbance observation method and conductance adding method in MPPT of photovoltaic array, the paper proposed a fast MPPT control method which combines constant voltage method with disturbance observation method. The method uses constant voltage method to obtain approximate voltage of maximum power point of photovoltaic array, then according to difference between output voltage of photovoltaic array and the approximate voltage to determine disturbance step: if the difference is big, it indicates that working point of photovoltaic array is far from maximum power point, the bigger disturbance step need to be used; if the difference is small, the smaller disturbance step need to be used, so as to reduce power oscillation. The results of simulation and experiment showed that the method not only can track maximum power point of photovoltaic array rapidly, but also can reduce power oscillation effectively.