In this study, using the finite element method analyzes stress and strain of device structure on different patterns epitaxial lift-off process. Design copper substrate bears stress 28.3 MPa and to simulate the change of the sacrificial layer in the epitaxial lift-off process, which setting the sacrificial layer etching amount for 10%, 30%, 50%, 70%, 90%. Besides, the stress and strain distribution of device structure analyzes on various sacrificial layer etching amount. Copper substrate is subject to tensile stress and its corner exist the maximum of stress and strain. Moreover, the stress distribution of epilayer concentrates in the upper and lower interface of sacrificial layer. The stress is larger sacrificial layer etching to 10% than etching to 90%. The structures 3 stress is relatively lower, which the stress reduces approximately half on etching amount 50%. Therefore, the GaAs epilayer not only reduce subjected to stress but also decrease the occurrence of defects.