In this paper,a novel quantum steganog raphy protocol via cavity quantum electrodynamics (QED) is proposed by using the evolution law of atom in cavity QED,whose hidden capacity is as high as four bi ts.The proposed protocol builds up a hidden channel to transmit secret messages through the entanglement swapping of any two Bell states in cavity QED.The proposed protocol not only needs no multipart icle quantum entangled state as the quantum resource,but also involves no entanglement swapping or quantum measurem ent about multiparticle quantum entangled state.Analysis shows that the proposed protocol is able to re sist the intercept-resend attack,the measure-resend attack and the entangle-measure attack,so it has good security.