The invention discloses a support type auxiliary flushing device and a method thereof. The support type auxiliary flushing device comprises the detachable upper portion and lower portion, wherein an insulation flushing mechanism is arranged on the upper portion, and a moving mechanism is arranged on the lower portion; the moving mechanism comprises a moving support, and a controller and a drivingunit connected with the connector are installed on the moving support; the insulation flushing mechanism comprises an insulation rod piece; the lower end of the insulation rod piece is installed on the moving mechanism, and a water gun is installed at the upper end of the insulation rod piece and further connected with a vertical lifting mechanical and a horizontal motion mechanism; and the vertical lifting mechanical and the horizontal motion mechanism are connected with a driving unit and used for adjusting the pitch angle and the rotating angle of the water gun on the support type auxiliaryflushing device correspondingly, so that the water gun is aligned with an operation object to assist a water flushing robot in flushing operation.