The invention discloses a mechanical structure of a humanoid edge climbing line patrol robot and an obstacle crossing method thereof, and belongs to the technical field of robots. The mechanical structure of the humanoid edge climbing line patrol robot comprises a frame; a first mechanical arm, a second mechanical arm, a third mechanical arm and a fourth mechanical arm capable of extending front and back in the walking direction of the frame are respectively arranged at four corners of the frame, and are respectively provided with a first manipulator, a second manipulator, a third manipulator and a fourth manipulator for grabbing lines from two sides; and mechanical wrists capable of rotating are arranged between all the mechanical arms and all the manipulators. Compared with the prior art, the mechanical structure of the humanoid edge climbing line patrol robot has the advantages of relief of the labor intensity, reduction of the operation cost and capability of crossing obstacles.