In an island mode of micro-grid , composed of photovoltaic array and storage battery in parallel connection, PV inverter in the V-f control model mainly adjust the frequency and voltage stability of the micro-grid system. When the output power of PV array can"t meet the demand of system and energy storage battery is confused by SOC limit, the inverter can"t satisfy the system stability.Aiming at this problem, based on the photo-voltaic maximum power tracking system and the characteristics of the energy storage battery charging and discharging system, the paper analyzes the improved V - f and P - Q model control algorithm, using P - Q model of micro gas turbine as back-up V - f model adjusting unit,and switching the photovoltaic inverter"s control mode to solve the problem of system stability. At the same time,the control strategy improve the utilization of renewable energy when the out power of PV array is surplus.The simulation verify the effectiveness of the control strategy by using PSCAD/EMTDC software.