The invention discloses a walking
reducer of an ultra-large hydraulic
excavator. The walking
reducer of the ultra-large hydraulic
excavator comprises a primary cylindrical gear reducing module, a secondary planetary reducing module and an external bearing module, wherein the primary cylindrical gear reducing module comprises a connecting cover, a
flange base, a primary cylindrical gear and a primary cylindrical gear shaft; the secondary planetary reducing module comprises a fixing connector, a spline connecting disc, a secondary rotary case, a secondary sun gear, a secondary planetary gear, asecondary planetary carrier, a secondary annular gear, a connecting ring, a primary rotary case, a gear shaft, a primary planetary gear, a primary planetary carrier and a primary annular gear; the external bearing module comprises an inner fixing connector, an inner sealing plate, an outer sealing plate and a limiting block. The walking
reducer of the ultra-large hydraulic
excavator is smaller instructural size under the same output power; the walking reducer is in double-
flange connection with a longitudinal beam frame, which is considerably higher in structural strength and rigidity than traditional single-
flange cantilever connection; the entire walking reducer is arranged inside the frame of the ultra-large hydraulic excavator to avoid the risk of collision with other objects, therebyimproving walking through performance and meanwhile being compact in structure and convenient to assemble and disassemble.