Abstract: In order to meet the engineering requirements and realize the multi-frequency transceiver sharing performance of the antenna, this paper proposes a new multi-frequency broadband multi-mode feed based on the mode-matching technique. The feed integrates S/ X/ Ka bands. The X/ Ka multi-band feed adopts the new X/ Ka broadband multi-mode horn and the X/ Ka and the Ka/ Ka band broadband demultiplexer. Compared with the existing conventional feeds, the bandwidth of the Ka-band is expanded, the bandwidth reaches 57%, and the efficiency of each frequency band has also been greatly improved. At the same time, the feed is designed based on the mode-matching technique, which greatly shortens the design time and ensures the design accuracy. Moreover, the multi-mode feed horn does not require high processing accuracy and is easy to manufacture, so it has great advantages in Ka-band. At present, the feed has been used in engineering, and all kinds of its performance are excellent.