Photonic applications in terahertz (THz) regime have attracted growing attentions in the past decades.Besides THz sources and detectors,passive components are also in high demand for guiding and manipulating THz waves.Devices like polarizers,switches and filters applicable in THz regions are thus in high demand.A number of materials have been investigated for these components.Among them,liquid crystal (LC) materials have raised wide interests due to their relatively large birefringence from the visible to microwave band,as well as the continuous tunability of birefringence induced by external field.Herein we propose and demonstrate two kinds of LC tunable THz photonic devices.