The invention discloses a transformer fault cumulative effect evaluation method based on a topological model of a power distribution network. The transformer fault cumulative effect evaluation method comprises the following steps of: depending on batch processing of a transient simulation program and a short-circuit current calculation program of simulation software PSD-BPA, completing a transformer cumulative effect evaluation function of the power distribution network by setting up a topological model of the power distribution network, calculating electric parameters and operation modes of the topological model of the power distribution network and the practical power distribution network, modifying the operation mode of a main network and a transient steady file, and setting up an end bus short-circuit fault simulation model of the power distribution network and a short-circuit calculation method; and, after the end bus of the power distribution network is failed, calculating short-circuit current flowing through a transformer via a transformer short-circuit fault current cumulative effect calculation model, superposing the short-circuit current with a cumulative effect initial value so as to obtain a transformer short-circuit fault current cumulative effect value, finally, outputting a result to perform graphical display, and performing evaluation. By means of the transformer fault cumulative effect evaluation method disclosed by the invention, condition early-warning and equipment overhaul preference strategies are provided for power distribution network equipment; and thus, the transformer fault cumulative effect evaluation method has good application prospects.