The invention discloses a cutoff measure cooperated power flow monitoring method of an electromagnetic ring network, and aims at providing the method which enables that a low-voltage line is not overcurrent when a high-voltage line is tripped and cut off and a cutoff measure is adopted in the high/low voltage electromagnetic ring network. According to different output of cut sets, the distribution coefficient of the high/low voltage electromagnetic ring network is calculated in a routine distribution coefficient method; power generation transfer factors of the low and high voltage lines are calculated in a power flow control method of the cutoff measure; the high/low voltage electromagnetic ring network is monitored according to a certain formula when the electrical network operates normally; and when the high-voltage line is tripped and cut off, a power scheduling control center adopts the cutoff measure to cut off the sets to ensure that the low-voltage line is not overcurret and ensure safe operation of the low-voltage line. The monitoring method is mainly applied to cutoff measures of the high/low voltage electromagnetic ring network.