The invention discloses a geometric model construction method and system for power transformers. The method comprises the following steps: carrying out structured grid division on a first type of members in the power transformers in advance so as to correspondingly obtain a first group of geometric models, carrying out unstructured grid division on a second type of members in the power transformers so as to correspondingly obtain a second group of geometric models, and storing the first group of geometric models and the second group of geometric models into a basic model base; providing a calling instruction input interface for a user so as to obtain a model calling instruction input by the user through the calling instruction input interface in a process of carrying out geometric modeling on a to-be-modeled power transformer; calling a corresponding geometric model from the basic model base by utilizing the model calling instruction; and constructing a transformer model corresponding to the to-be-modeled power transformer according to the called geometric model. The geometric model construction method and system for power transformers can be used for realizing the aim of efficiently and rapidly constructing the geometric models of the power transformers.