The invention provides a line fault analysis method based on network message data between transformer substations. According to the line fault analysis method, network message information in a fault time quantum of a fault line is obtained, network message data at the two ends of the line are fused, and according to the fused data at two sides, differential fault decision accounting is carried out on the line at last. When a computation result reaches a differential condition, a line fault analysis result is given. According to the technical scheme of the line fault analysis method, fault analysis of network messages between the transformer substations is achieved, a novel means is provided for the line fault analysis crossing the transformer substations, and meanwhile a referential basis is provided for deciding on post-accident protection behaviors.