The present invention provides an electric system online hybrid simulation method and system. The method comprises the steps of: based on historical simulation data, combining a risk fault set by employing risk faults screened out according to a preset condition; according to faults in the risk fault set, performing data integration to obtain hybrid simulation calculation data; and performing simulation based on the hybrid simulation calculation data and the risk fault set. The method and the system employ configuration of screening and then simulation, and combine fault screening and data integration to effectively improve the automation degree of the hybrid simulation applied to online analysis.