Abstract: A polarization network on radio telescopes generally consists of a polarizer, a waveguide-to-coax adaptor, and a directional coupler etc. Usually, in order to obtain the maximum system sensitivity, the polarization network will be worked at 20 K platform in the cryostat of cryogenic receivers,which decreases the receiver noise temperature to lowest.Through in-depth study of the polarization network, this paper designs an X-band polarizer,coupler and waveguide-to-coaxadaptor integrated structure based on a septum structure. This design not only realizes the conversion of circularly polarized wave to linearly polarized wave, but also obtains the noise coupling of -30 dB. The measured results show that the design has good axial ratio, coupling and VSWR characteristics. Meanwhile, the integrated design further reduces the cascading between passive devices to get the lowest insertion loss of the feed network in front of the cryogenic low noise amplifier,which enhances the receiving sensitivity of the radio telescope.