By forming simultaneously photosensitive layers on both-sides of cellulosetriacetate film with chemical reaction, we obtained a holographic recording film withstratified sensitivity─dichromated cellulose triacetate(DC-TAC ). The stratifiedvolume holographic gratings(SVHG)recorded on the film have, to our best knowledge,the highest 1th-order experimental diffraction efficiency(54%).In this paper, themaking method and the micro-mechanism of forming SVHG are described.The strictlyperiodic selectivity of the SVHG is given. In addition, the difference of the diffraction efficiency of double-layer SVHG between the experimental value in DC-TAC and the theoretical prediction is discussed. The effective way for futher improving the diffraction efficiency and the potential applications of the SVHG in some interesting fields are suggested.