The photonic crystal liquid crystal fiber grating (PCLCFG) is produced by filled the helix liquid crystal in the photonic crystal fiber core air column. The transmission characteristics of the PCLCFG is study by space filling mode and the mode coupling theory as well as the transmission matrix, and has carried on the theoretical calculation and the simulation with Matlab. The results show that to the pitch the typical liquid crystal which increases with temperature increment, the resonant wave length red shift, band width reduces, time delay increases, the normalized frequency reduces, the boundary of single model and multi-mold approaches to the multi-mold of PCLCFG. It is the remarkable that of the temperature sensing characteristics of the PCLCFG.