Abstract: In this paper,a new method is presented to provide the tidal model under open boundary condition,in which the theory of the data-driven model is integrated with the tidal model,and the tidal current field data is imported,too.The approach constructs solution space of internal observation site with the results of numerical simulation cases,and describes the relationship between the internal observation site and the open boundary.And the filed data are imported into the relationship to inverse the open boundary condition.A case study of K₁ tidal constituent amplitude in Liaodong bay is presented for the validation of the method.The maximum error of K₁ tidal constituent amplitude is 0.008 m,and the results show that the method is efficient for inversing the open boundary condition.