One-dimensional (1-D) photonic crystals(PCs)with liquid crystals (LCs) are promising in various applications such as filters, low-threshold lasers, optical switch. In the present paper, the authors investigated the transmission spectrum of 1-D PCs with LCs for defect layer at different voltages ranging from 0 to 10 V. The tunable spectral range was about 50 nm, FWHM of the transmission peak was 18 nm and the band gap was nearly 400 nm. Furthermore, we presented a kind of polarization insensitive LC photonic crystal, and designed a 1-D LC photonic crystal device that has double LC layers with zero twisted angle. Double LC layers have a function of compensation for both polarization components of incident light, which makes the original two transmission peaks in the band gap to incorporate to one, and enhances the light intensity and filter performance.