Expandable profile liner （EPL）technology is mainly used to solve technical problems such as frequent accidents in complex deep boreholes and limitation of casing tiers. Hydraulic Expansion of EPL is a key link in the application. In order to study the mechanical properties of expandable profile liners under hydraulic expansion, and improve the treatment of downhole accidents, the finite element numerical simulation and indoor laboratory tests were combined to study the hydraulic expansion process of expandable profile liners (EPL). Through multiple laboratory tests on hydraulic expansion of EPL, and comparison of the results with those of the finite element theoretical analysis, it was found that both methods obtained basically consistent results. The elastic deformation pressure of EPL is 0 to 2.5 MPa, and the displacement rate of the key points on the cross-section is larger when the pressure of the liner string is 3 to 9 MPa; the hydraulic expansion pressure of EPL is 14 MPa; and the maximum and minimum diameter for the cross-section dimension of EPL after expansion Xmax are 136.98 mm and 104.58 mm; which meet the requirement of the cross-section size for mechanical expansion of EPL. It provides important theoretical basis and technical support for field experiment and industrial application of EPL.