The utility model discloses a fold-back type stair drop well, relates to the field of drainage engineering, and particularly relates to concrete structures with drop water in a city drainage pipeline. The drop well is applicable to the drop well with the pipe diameter d of 700-1650 mm of rainwater pipe or sewage pipe and the dropping difference of 2-6 m. The drop well is mainly composed of a well body, a partition wall, a drop water chamber, an operation room, a water inlet pipe and a water outlet pipe. An upper step-plate, a middle step-plate and a lower step-plate are arranged in the drop water chamber, the three step-plates are arranged in a mutually fold-back state, and the dimension of the drop well can be reduced effectively. The fold-back type step drop well overcomes the defects that in the prior art the dropping difference of large pipe diameter drop wells is small. The dimension of the drop well is reduced by the adoption of fold-back arrangement of steps, the space below the steps can be used effectively, the volumes of concrete filling or brick setting and foundation pit excavation project amount are reduced, the construction cost is lowered, and the drop water chamber is separated from the operation chamber so that maintenance and operation in the drop well can be facilitated.