The invention provides a feed mode switching mechanism of a radio telescope. The feed mode switching mechanism of a radio telescope comprises a main reflecting surface and an auxiliary reflecting surface arranged on the main reflecting surface through an auxiliary reflecting surface support, the auxiliary reflecting surface support comprises a first supporting leg and a second supporting leg whichare arranged oppositely, the first supporting leg is connected with a main focus receiver platform through a rotating hinge, one end of the main focus receiver platform is a hinge end connected withthe rotating hinge, and the other end of the main focus receiver platform is provided with a lock head. The feed mode switching mechanism adopts a reversible main focus receiver platform, does not cause any additional shielding on the main reflecting surface and the auxiliary reflecting surface in two observation modes, and the driving mechanism is arranged on the supporting legs, so that the panel precision and the position precision of the auxiliary reflecting surface are not influenced; in addition, the feed mode switching mechanism is based on the driving mechanism and ropes, and utilizesthe lowest pitch angle state to switch the observation mode, so that short switching time can be achieved under the condition of low power of the driving motor, and the stability and controllability of the switching process are also ensured.