The purpose of this study is to compare aerodynamic characteristics of flight motion between rigid and elastic wing. Especially, in Elastic wing we investigate about wing of partially different Young ' s modulus. In order to this investigation, we used Fluid-structure interaction (FSI) analysis. In FSI anaiysis , fluid analysis employ finite difference method (FDM) and structure analysis employ finite element method (FEM). Computation of flapping wing motion are performed for various Young ' s modulus condition, we survey relationship between lift coefficient, thrust coefficient and displacement.