In order to reduce communication traffic of wide area protection（WAP），adaptive identification rule and its realization method for WAP are proposed.The effects of short line circuit，complex faults and high resistance grounding on sequence voltage distribution are discussed，combining sequence voltage distribution characteristics when fault occurs.Various bus sequence voltages in the wide power grid area are real-time monitored and ranking calculated by expert system，and fault region is analyzed on the basis of ranking results so as to realize the adaptive identification fault region.Communication traffic is dramatically reduced when system only communicates with intelligent electronic devices（IEDs）in the fault region.Different from the past WAP fixed partition，the method of adaptive identification of fault region for WAP is easier to get high sensitivity fault signal by monitoring the sequence voltage identification fault region of startup buses，meanwhile，the method is immune to structure change of power system.The simulation experiment verifies the validity of this method.