The invention relates to a distinguishing method for equipment failures of a regional power grid, in particular to an intelligent on-line distinguishing method for main equipment failures of the regional power grid. According to the method, an SCADA system is combined to acquire original data, failure data are filtered automatically, bad data are removed, the data which are likely to be lost are marked, failure data chains which are connected with one another according to the actuation time sequence of switch and guard signals are formed instead of just being limited to failure trip signals, telemeasuring data changes are effectively combined to be used as a failure judging basis together, hence, logical, methodical and effective analysis of switch remote communication deflection and telemeasuring data changes can be achieved, at last, operation specification failure diagnosis based on a Petri net diagnostic method and a power grid can be achieved on the basis of the data chains, and failure point information can be acquired.