The embodiment of the invention discloses a focusing system for an antenna feed source. The focusing system comprises a waveguide, wherein the front end of the waveguide is provided with a feed source, and the rear end of the waveguide is provided with a lead screw nut; a lead screw sleeved with the lead screw nut; a driving motor, wherein the output shaft of the driving motor is coupled to the lead screw for driving the lead screw; and a linear guide rail provided with a guide rail slider and connected to the waveguide. The focusing system is provided with the driving motor and the lead screw, and the lead screw nut is fixed to the rear end of the waveguide. The driving motor moves the lead screw in order that the lead screw nut moves the waveguide horizontally when moving along the horizontal direction, thereby moving the feeding source in the horizontal direction and electrically focusing the feed source. As a result, a worker can adjust the position of the feed source by controlling the drive motor on the ground.