Abstract: The present invention provides a polarizing film with high polarization degree and high transmittance, which is directed to the use of polyvinyl alcohol (PVA)-based film by subjecting to a monoaxial multi-step dry-stretch process, thereafter conducting a swelling process in a water-washing tank, cross-dyeing in a dyeing-crosslinking tank comprising an aqueous iodine containing solution, then subjecting to a post stretch process in an stretch tank 05 comprising PVA crosslinking agent, as to obtaining a polarizing film with a transmittance of at least 43% and a polarization degree of at least 98%; and the producing method thereof, a polarizing plate and an optical component produced from the same.