Abstract: The method of tension winding of fiber bundle is an effective way to improve the radial strength of flywheels. An approach of calculating the initial stress and deformation in tension winding according to misfit is advanced. The results show that the hoop stress decreases firstly and then increases while the radial compression stress decreases all the while in the qually winding tension. While in changed winding tension which is enhanced from lower to higher levels, the radial compression stress can be increased. It is not sufficient to use tension winding only in flywheel design. The tension winding and process of pressfit should be used together to design the rational initial radial compression stress.