The invention discloses an optimal model selection method for improving the operating state measuring precision of voltage transformers. The method includes the following steps that (1), an input parameter set PJ for optimal model selection of the voltage transformers is generated; (2), the total model selection evaluation score F of each voltage transformer to be selected is calculated; (3), the total model selection evaluation scores F of all the voltage transformers to be selected are ranked, and the voltage transformer with the highest total score F is in the type with the optimal operating state measuring precision. The optimal model selection method for improving the operating state measuring precision of the voltage transformers is applicable to plant model selection of the power voltage transformers, fills in a gap in the optimal model selection of the operating state measuring precision of the voltage transformers and has good application prospects, and as the evaluation scores of the operating state measuring precision of all the types to be selected are output, a designer can achieve balance between technicality and economical efficiency.