The influences of different Young's moduli on the distribution of the stress and displacement of a composite flywheel was investigated in this paper.According to the heterogeneous anisotropy elastic theory and design features of the flywheel,the computation formulas for the stress and displacement of the composite flywheel were established at working speeds,and the radial stress,circumferential stress and radial displacement at an arbitrary point were presented.Then,based on the computation models above,the influences of different positions and rotational speeds on the radial stress,circumferential stress and radial displacement were discussed.It is concluded that the radial stress,circumferential stress and radial displacement all increase with increasing of angular velocity from 0 to 5 000 rad/s.The maximal radial stresses of two kinds of materials all occur at the exterior margin of flywheel and the maximal circumferential stresses occur at the inner margin of flywheel.Moreover,under the situation of high Young's moduli(Er=100 GPa,Eθ=350 GPa),radial and circumferential stresses are all higher than that of low Young's moduli (Er=20 GPa,Eθ=150 GPa),whereas,the displacement shows an oppisite change.