Microstructure optical fiber materials has many virtues: small momofilament diameter, soft and flexible, high resolution, which make it have many broad application prospects in different fields, such as: high definition imaging equipment, industrial automation dectection, military and aerospace, etc. The materials of core, cladding and acid-soluble glasses were prepared, which had good physical and chemical matching on the base of three layers coaxial micro-structure. The double clad flexible fiber micostructure and spectral performances were tested. The experiments obtained high quality image transfer fiber, of which monofilament diametre is 10μm ± 0.1μm, resolution is 52.5LP/mm, transmittance is 42.6%/m. Experimental results showed that the preparation process broke through the traditional techniques and achieved the structure innovation, which had some reference value to improve the optical properties of image instruments.