A flywheel is a device which stores energy when the supply is more than demand and releases when the supply becomes less. This paper presents analysis of composite flywheel includes stress and thermal analysis. While the machine is operated, stresses are induced on the flywheel the induced are due to centrifugal forces, due to change of speed and load and shrinkage stress due to unequal rate of cooling and casting. In this paper, stress and thermal analysis and find that amount of energy stored, critical stress regions and overall stress distribution along with heat distribution are performed. By knowing the above terms we can take necessary measure to prevent the damage occurred and improve the efficiency either by increasing the energy stored or by changing the type of material we use. By improving the energy storage and thus an increase the speed of the flywheel there by meeting needs with less amount of input. © 2016, International Journal of Pharmacy and Technology. All rights reserved.