The bearing capacity of water-lubricated bearings with bearing bush elastic deformation is calculated by fluid-structure interaction (FSI) of ANSYS finite element software and compared to the case without elastic deformation. The influence ranges of bearing bush elastic deformation on bearing capacity under different eccentricities and speeds are specifically analyzed. Under the condition of the preferred modulus value of bearing bush material is 1 000 MPa, the influence of elastic deformation on bearing capacity increases sharply when the rotational speed exceeds 1 000 r/min and eccentricity is greater than or equal to 0.8. The results obtained through calculation and comparative analysis are not only the technical references for the study of bearing performance of water-lubricated bearings, but also the bases for the selection of bearing bush materials and structural design of water-lubricated bearings.