The invention relates to an electrostatic dust removing device for exhaust gas treatment. The device comprises a casing, a purification pipe and a processor. The inner walls of two sides of outer casing are provided with openings, the upper and lower sides of the openings are provided with power supply components, a switching component is arranged in the casing, and the switching component comprises a connecting block, a cleaning component, a plurality of electrode plates and two switching units. The cleaning component comprises a translation block, a translating plate, a first spring, a cleaning plate, a plurality of brushes and two lifting units. Each of the power supply components comprises a notch, a second spring, a pressing plate, a vertical rod, a conductive block and the two limiting units. The electrostatic dust removing device for exhaust gas treatment drives the electrode plates to move into the openings through the switching component, the electrode plates are fixed by thepower supply component for power supply, an electric field is generated between the electrode plates to adsorb dust particles, then the switching unit operates, the cleaning component drives the brushes on the cleaning plate to move on the electrode plates, the dust particles are swept off, when the electrode plates return to the openings, the dust removal efficiency is ensured, and the practicality of the device is improved.