The invention relates to a ridge loading zigzag waveguide slow wave line which belongs to the technical field of microwave vacuum electrons and relates to a traveling wave tube amplification device. The device is formed by connecting a series of arc bending waveguides (or right-angle bending waveguides) and straight waveguides end to end, i.e. bending rectangular waveguides into a U-shaped zigzagline (or a right-angle zigzag line) periodically along the electric field surface, so as to form a zigzag waveguide structure. A metal ridge sheet with a certain thickness is loaded on the inner wallsof the straight waveguides of each zigzag unit, and the waveguide walls and the metal ridge sheets are provided with round through holes along the position of a middle axle symmetric line of a slow wave structure, wherein the round through holes of the straight waveguides of two adjacent zigzag units are connected through a metal pipe with an aperture size the same as the aperture size of the round through hole so as to form an electron bunch passage. The invention can improve the coupling impedance of a zigzag waveguide slow wave system, thereby ensuring that a zigzag waveguide traveling wave tube has higher gain and efficiency.