NOVELTY - Use of three-screw internal mixer extruder for spinning micro-pore indium tin oxide type fiber, is claimed, where the application method comprises mixing indium precursor and tin precursor, 1/1000-1% of surface active agent, 1-5% of bonding agent and 1/1000-5/1000% of sol gel stable auxiliary agent with the solvent using a three-screw internal mixer extruder at 5o-380 under a pressure of 7-17 MPa, stirring to uniformly mixing the raw materials, reacting for 20-28 hours in supercritical fluid, and gradually compacting a homogeneous body of compression zone into supercritical fluid by screw.    USE - The three-screw internal mixer extruder is useful for spinning micro-pore indium tin oxide type fiber (claimed), which is useful in flat panel display, solar battery, sensor, electro chromic smart window, windshield, ice chest and microwave shielding chest and microwave shielding protective mirror and solar cell functional glass and broad frequency spectrum light camouflage hiding material and military field.    ADVANTAGE - The extruder prepares micro-pore indium tin oxide type fiber with good transparent heat insulation effect.    DETAILED DESCRIPTION - Use of three-screw internal mixer extruder for spinning micro-pore indium tin oxide type fiber, is claimed, where the application method comprises mixing indium precursor and tin precursor, 1/1000-1% of surface active agent, 1-5% of bonding agent and 1/1000-5/1000% of sol gel stable auxiliary agent with the solvent using a three-screw internal mixer extruder at 5o-380 under a pressure of 7-17 MPa, stirring to uniformly mixing the raw materials, reacting for 20-28 hours in supercritical fluid, gradually compacting a homogeneous body of compression zone into supercritical fluid by screw, filtering homogeneous body through a filter media in a filter section to remove impurities, and then adding catalyst into residue for performing polymerization, precisely controlling the fiber fineness and uniformity using a metering pump connected with a melt metering gear, connecting a flowing section and an expanding section from a die head spinneret hole extrusion of the extruder by a melt-blown die head inlet, extruding from the die head of a spinneret hole connected with flow body to reduce the swelling expansion, passing high speed hot air at two sides of the extruder for viscous flowing of the melt is rapidly attenuation, cooling and solidifying the flowing melt to obtain superfine hole type fiber, and drying and calcining process the fiber to obtain end product, where the ratio of indium-tin ion is 90:10-80:20, and metal ion concentration of 0.6-0.7 M.