Abstract: A simple model was established, the polarization extinction ratio（PER） expression of cystalclab fiber-optic polarizer was presented based on geometrical optics. The variation of the PER versus the diameter of biconical taper waist and the length of cladding was analyzed. Considering the intensity of biconical taper waist, the manufacturing parameters of polarizer were optimized and analyzed,corresponding experiment was carried out. The experiment verifies that the PER is more than 30 dB and its insertion loss（IS）is less than 0.5dB. The variation of the PER is less than 1.5dB and the variation of the IS is less than 0.5dB in the temperature range of -50 ℃~+70 ℃. This kind of polarizer is fine in tempreture performance and stability.