Abstract: For getting superior quality and denser WDM device, a new method to make demultiplexing device with volume holographic technology is studied. Based on coupledmode theory, the fundamental principle that photorefractive volume grating is used as a wave filter for WDM is discussed. The equations of optimum beam ratio,strength of coupling and corresponding maximum diffraction efficiency are described. The effects of the relation on recording geometry with effective electrooptical coefficient and space charge field, wavelength of diffraction beam and diffraction angle on exposure sequence are taken into account, and the perfect exposure sequence is discussed based on recurrence method. A highluminosity halogen lamp is considered as the multiplex photosource and an experimental scheme of 16 channels wave demultiplex based on volume holographic technology is designed. The device can separate the line which wavelength space out 0.8mm to 1.0mm distance and fit in demultiplexing for crowed wave.