The invention discloses an assembly tool of an escalator bridle. The assembly tool includes a horizontal support frame, a left limiting plate, a left working plate, a left rear working plate, a right limiting plate, a right working plate, a right rear working plate, a first sighting device, a second sighting device and a position-fixing and hoisting assembly; the left limiting plate is arranged at the left end of the horizontal support frame, the left working plate is fixed in a left-and-right moving mode relative to the left limiting plate, the left rear working plate is fixed in a front-and-back moving mode relative to the left limiting plate, the right limiting plate is arranged at the right end of the horizontal support frame, the right working plate is fixed in a left-and-right moving mode relative to the right limiting plate, the right rear working plate is fixed in a front-and-back moving mode relative to the right limiting plate, the first sighting device is arranged at the front end of the horizontal support frame, the second sighting device is arranged at the rear end of the horizontal support frame, the two ends of the position-fixing and hoisting assembly are detachably connected with bridles on the two sides, and the position-fixing and hoisting assembly includes a third sighting device. The assembly tool of the escalator bridle is simple and reasonable in structure, can rapidly and accurately fix the position of the escalator bridle, after the assembly tool is debugged for the first time, no large-scale disassembly debugging is required, and moreover, welding does not need to be completed on the assembly tool.