The invention discloses a dual-frequency wave guide tube which comprises an outer wave guide tube and an inner wave guide tube, wherein the outer wave guide tube is used for receiving low-frequency-band satellite signals, and the inner wave guide tube is used for receiving high-frequency-band satellite signals; the outer wave guide tube is provided with a first wave guide space, wherein one end of the first wave guide space is opened, and the other end of the first wave guide space is closed; the inner wave guide tube is fixedly connected to the outer wave guide tube and provided with a second wave guide space, wherein a dielectric material wave guide part is coaxially plugged in one end of the second wave guide space; and at least part of the second wave guide space and the first wave guide space are coaxially located in the outer wave guide tube. Therefore, when the dual-frequency wave guide tube is erected on a dish antenna, the first and second wave guide spaces of the outer and inner wave guide tubes can be coaxially arranged in the reflecting focal positions of the dish antenna so as to respectively receive satellite signals with different frequency bands.