Disclosed are an island control method and system suitable for a solar energy storage power generation system; according to the method, firstly, the inversion output power and the load power of an inverter are obtained; then, according to preset logic, the inversion output power and the load power, the inversion output power is adjusted so as to enable the load end voltage to be abnormal along with the adjustment of the inversion output power when the island occurs; and finally, when it is detected that the load end voltage is abnormal, a commercial power relay is disconnected, and the cuttingoff of the commercial power and the solar power generation system is realized. According to an energy positive feedback mode, when the commercial power is lost, the load end voltage is in fast avalanche, and the abnormal protection of the power grid is triggered to disconnect the connection between the load end and the power grid, so that the influence of wide working commercial power frequency range and the large commercial power voltage fluctuation of the solar energy storage power generation system can be avoided, and the island control of the solar energy storage power generation system is realized.