Induced gluon radiation and energy loss of heavy quark in hot and dense QCD media are discussed. Using the light-cone path integral approach, an analytical formula of the energy loss of heavy quark is derived. The results show that the quark energy loss obviously depends on the mass of quark, i. e. a remarkable suppression occurs in the case of heavy quark comparing to a light one. The radiative energy loss of energetic quark is proportional to L2, where L is the length of the medium. The dependence of energy loss on L2 turns to L with decreasing quark energy.