The invention relates to a construction method of sleeving a casing pipe in a working pipe, which is applied to installation engineering of oil pipes, natural gas pipelines and other pipelines. The invention can overcome the problem of high construction cost in the current pipeline installation engineering. According to the technical scheme, the method comprises the following steps: firstly, excavating a pipe floating pit, mounting locating piers at the bottom part of the pipe floating pit, inserting pipe stabilizing rod elements in the locating piers, mounting guide rails on the two sides of the ground of the pipe floating pit, spanning a rail car on the guide rails, and mounting bearing pipes and pipe lifting ropes on the rail car; and then, fulfilling clear water in the pipe floating pit, sealing the pipe orifices on the two ends of the working pipe, dragging the working pipe into the water and locating the working pipe through the pipe stabilizing rod elements; and finally, bundling a light material at the outside of the casing pipe, mounting a hook at the top part of the casing pipe, lifting the casing pipe to the end port of the working pipe through the rail car, adjusting the height of the rail car so that the pipe orifices are jointed, starting the rail car to sleeve the casing pipe in the working pipe and moving the casing pipe to the other end. The equipment used in the construction method has the advantages of small power, simple structure and low cost; and the construction method can be used for reducing the workload and is safe in construction, high in efficiency and good in installation quality.