The invention provides a three-cabin truss and a three-cabin pipe gallery bridge and relates to the field of long span trusses and equipment. The three-cabin pipe gallery bridge comprises a bridge pier, a water supply and drainage pipeline, a gas transmission pipeline, a power communication cable and a three-cabin truss. The three-cabin truss comprises a truss body and a supporting device, wherein one end of the supporting device is fixedly connected with the bottom of the truss body, and one end, far away from the truss body, of the supporting device is arranged on the bridge pier. The truss body comprises a water supply and drainage cabin, a power communication cabin and a fuel gas cabin, wherein the water supply and drainage cabin is connected with the power communication cabin, the power communication cabin is connected with the fuel gas cabin, the water supply and drainage cabin is used for containing the water supply and drainage pipeline, the power communication cabin is used for containing the power communication cable, and the fuel gas cabin is used for containing the gas transmission pipeline. Compared with the prior art, the three-cabin truss provided by the invention has the advantages that various pipelines and circuits inside the three-cabin truss are effectively integrated, classification treatment is realized, management difficulty is greatly reduced, and mounting and maintenance are facilitated.