The characteristics of polymer dispersed liquid crystal (PDLC) and holographic polymer dispersed liquid crystal (H-PDLC) volume grating are introduced. Based on the novel H-PDLC volume gratings, series-connecting dynamic gain equalizer design is provided. Furthermore, simulations are made about wavelength selectivity of H-PDLC grating at 1550 nm and the function of H-PDLC dynamic gain equalizer. The calculation results show that when suitable grating parameters of H-PDLC are selected, half spectral width of grating is about 10 nm at central wavelength of 1550 nm. And the fluctuation of spontaneous emission spectra of erbium-doped fiber amplifier (EDFA) can decrease from 3.3 dB to 0.1 dB within 1530 nm to 1560 nm based on H-PDLC dynamic gain equalizer.