The invention relates to a transmission characteristic simulation method and system for partial discharge ultrahigh-frequency electromagnetic wave signals of a transformer. The method is characterized by comprising the following steps: (1) conducting self-adaptive grid dividing on a transformer model constructed in advance; (2) setting a stimulated partial discharge signal source; (3) setting more than one data collection point in different positions of a transformer; and (4) obtaining respective collection results of all data collection points after a preset period of time for stimulation, and obtaining the ultrahigh-frequency transmission characteristics of local discharge signals in the transformer according to analysis of collection results of the data collection points. The application proves that the research on the transmission characteristics of partial discharge ultrahigh frequency electromagnetic wave signals is effectively and accurately achieved through a simulation mode. The transmission characteristic simulation method and system can be used for researching the transmission characteristics, such as attenuation rules and frequency spectrum distribution rules, of partial discharge ultrahigh frequency electromagnetic wave signals in a transformer.