The invention provides a main/substation information interaction method applied to power system state estimation. The method comprises the following steps: step 1, a main scheduling station receives a data message with a substation topology model and equipment measurement quality state analysis result transmitted by a substation; step 2, the main scheduling station transmits the equipment measurement quality state analysis result in the received data message to the main station state estimation for measurement weight modification, compares substation topology identification result with topology analysis result of a same factory station corresponding to the main station state estimation, executes the step 3 when the comparative result is not accordant, and ends the interaction process of the substation and the main scheduling station when the comparative result is accordant; step 3, the main scheduling station transmits a detailed model request to the substation; step 4, the substation transmits a substation telecommand value with switch and disconnecting link position information to the main scheduling station, and the main scheduling station performs detailed model verification. By adopting the method provided by the invention, the telecommand identification and telemetering quality state result of substation state estimation are sufficiently utilized to perform on-line state estimation calculation, and the accuracy in topology analysis and estimation calculation of substation state estimation is improved.