The invention relates to an integrated navigation system recursion optimizing initial-alignment method based on polarization information. The method is characterized in that positions and speed output by a ship's inertial navigation system (SINS) are corrected with the help of a global position system (GPS), and azimuth angles output by the SINS are corrected by using polarizing angle information provided by a polarization sensor. A recursion robust filter is adopted to restrain model errors in an inertial device and filter interference like noise of a part of devices. The initial-alignment method has the advantages that compared with an SINS/GPS integrated navigation system without the polarizing angle information, alignment time is shortened on equal conditions. The integrated navigation system recursion optimizing initial-alignment method has the advantages of being fast in alignment, strong in anti-interference capability and the like, and the integrated navigation system recursion optimizing initial-alignment method can be applied to an initial-alignment process of integrated navigational devices for airplanes, steamships and vehicles.