Electrical tuning of defect modes in a one-dimensional (1D) photonic crystal (PC) has been demonstrated using a ferroelectric liquid crystal (FLC) and a nematic liquid crystal (NLC) defect layers in the periodic structure. The transmission peak intensities for defect mode depends on the angle between LC molecular axis and polarization direction of the incident light. At defect mode wavelength, the 1D PC with LC defect layer transmits only the light with the polarization direction determined by the direction of extraordinary or ordinary optical axes in LC defect. Polarization direction of the light propargating through the 1D PC with in-plane NLC defect can be controlled based on field-induced in-plane realignment of NLC molecules.