The utility model relates to a suction nozzle of electric dust collector including a dust-absorbing unit, a connecting piece and a dust-sweeping unit. The dust-absorbing unit has an open part for absorbing dust on the under cleaned surface. One end of the connecting piece is connected with the upper part of the dust-absorbing unit and the other end is provided with a connecting pipe. The dust-sweeping unit is arranged in the dust-absorbing unit for sweeping dust. The open part, the connecting piece and the connecting pipe are all arranged with channel parts inside to make the absorbed dust go through. Relative to the dust-absorbing unit, the connecting piece can be rotated at a direction which is approximately paralleled to the under cleaned surface. The connecting piece will rotate to stop when the long axis directional central axis of the dust-absorbing unit is approximately paralleled to the long axis directional central axis of the connecting pipe. As the connecting piece is connected with the upper part of the dust-absorbing unit, when the long axis directional central axis of the dust-absorbing unit is approximately paralleled to the long axis directional central axis of the connecting pipe, the connecting piece and the connecting pipe are both located above the dust-absorbing unit.