The invention relates to a novel transformer state estimation method based on field-circuit coupling analysis. The method comprises steps as follows: a transformer model is established, and a transformer electromagnetic field is analyzed with a finite element method; a working state of a system where a transformer is located is analyzed and is equivalent to a lumped parameter circuit model in a corresponding state, and circuit analysis is performed; a field-circuit coupling mathematical model of the transformer is obtained on the basis of electromagnetic field analysis and circuit analysis; finite element software is adopted for calculation, a vector magnetic potential A of each node in solution space of the transformer is obtained, other physical quantities such as winding current, impedance and the like of the transformer are solved, and electromagnetic field distribution of the transformer, electromagnetic force borne by a winding and loss of all parts of the transformer are obtained; loss values of all parts of the transformer are taken as heat sources to be loaded to a transformer temperature field model, and transformer temperature field distribution is obtained with a finite volume method. Therefore, estimating analysis of multi-aspect states such as the electromagnetic field distribution of the transformer, the electromagnetic force borne by the winding, temperature field distribution and the like when an electric power system is in different states is realized, basis is provided for overhauling and maintaining work of the transformer, and the working efficiency is improved.