The invention discloses a roof end-beam structure of a low-floor tram. The roof end-beam structure comprises a roof end beam, an upper hinge support seat, an upper hinge mounting seat and an end wall board, wherein the roof end beam is welded with the front end of a roof board; both ends of the roof end beam and both ends of the roof board are all welded with roof edge beams; the upper hinge support seat is hinged with the upper end surface of the roof end beam; the upper hinge mounting seat is mounted at the front end surface of the upper hinge support seat; a flange for retaining water is arranged at the front end of the upper end surface of the roof end beam; the end wall board is riveted to the front end surface of the roof end beam and below the flange; and waterproof glue is arranged in the gap between the flange and the upper end of the end wall board. Compared with the prior art, the roof end-beam structure of the low-floor tram has the advantages of simplifying the overall structure and ensuring the flatness of the roof end beam so as to meet the installation requirements of joints of the upper hinge mounting seat and the like while satisfying the strength and rigidity of a tram body, effectively preventing water seepage in the rain by adding the design of a water-retaining structure, and facilitating the process operation and beautifying the appearance by gluing after the riveting of the end wall board.