The invention provides a fast identification method for secondary enrichment of residual oil in high water-content later period in a complex fault block oil reservoir. The fast identification method comprises the steps that a target oil reservoir is measured to obtain geologic parameters and well network parameters of the target oil reservoir; according to the geologic parameters and the well network parameters of the target oil reservoir, a primary physical model of the target oil reservoir is established; based on the primary physical model of the target oil reservoir, fitting calculation is conducted according to a streamline stream tube method, dynamic fitting characteristics of an oil production well and a saturation field before secondary enrichment of the residual oil are obtained, and the primary physical model of the target reservoir is corrected to obtain a corrected physical model; and based on the corrected physical model, calculation of vertical enrichment and horizontal enrichment is conducted on joints in the enrichment process of the residual oil, the reservoir saturation and water content of the joints are obtained, and identification of secondary enrichment of the residual oil in high water-content later period in the target oil reservoir is achieved. The method can accurately predict the change condition of displacement leading edge dynamic parameters.