On-line extension device for drainage pipeline

The utility model discloses a drainage pipeline on-line extending device which comprises a movable trailer, a drainage assembly, a pipeline extending piece and a sewage temporary storage assembly, the drainage assembly comprises at least two drainage pipelines arranged on the movable trailer side by side, power pieces are arranged at the water inlet ends of the drainage pipelines, and control valves are arranged on the drainage pipelines; the pipeline extending part is connected to the water outlet end of the drainage pipeline and used for being connected with the extending pipeline, and the lengths of the extending pipelines connected with the drainage pipelines of at least two different routes are different. The sewage temporary storage assembly is mounted on the movable trailer, is connected with the drainage pipeline and is used for collecting sewage located at the rear end of the control valve when the control valve is closed and the extension pipeline is continuously connected. The multiple sets of drai