The total internal reflection-photonic crystal fibers (TIR-PCF) are proposed by filling the air hole of solid-core PCF clad with nematic liquid crystal which the refractive index is less than that of background glass within the temperature and wavelength in research. The effective index of clad with filled liquid crystal is put out by the fundamental space filling mode index. The temperature sensor properties in the PCF are studied by the step effective index model, and numerical calculation is carried out. The results show that the effective index of clad and equivalent core radius increase with temperature increasing, and increase quickly about clear point of liquid crystal. The cutoff wavelength of the second mode decrease with temperature increasing, and decrease quickly about clear point of liquid crystal in the PCF infiltrated with liquid crystal.