The invention discloses a wind power station island emergent cutting method based on mixing index. When a junctor of the wind power station breaks down, two index including voltage and frequency, which are closely related to the self-protection of a blower fan. Mixing weight is conducted on the voltage and frequency based on the change speed ratio, obtaining an integrated cutting index. Priority division is conducted on the blower fan in the wind power station by means of the integrated cutting index. The blower fan having high priority is cut at first to stabilize the whole wind power stationand prevent the network removing of the linked blower fan caused by index deterioration. The invention is advantageous in that the aim of stabilizing the index of the wind power station can be achieved; it is guaranteed that when the junctor breaks down, the wind power station can stably pass the island operation period; compared with other cutting method, the two important indexes of voltage andfrequency are taken into consideration comprehensively; operation is simple; feasibility and utility are good.