The present invention relates to an automatic cleaning device for suction port of electric submersible pump. The pipe string joint is connected between the oil pipe and the electric submersible pump. A plurality of oil drain passage inlets, steel balls, return springs, sealing plugs and oil drain passage outlets are evenly distributed in circumferential direction of a boss. The upper end of the connecting pipe is connected with the outlet of the oil drain passage, and the lower end is connected with the nozzle. The retaining ring secures the connecting pipe on the housing of the electric submersible pump. A high-pressure fluid ejected from the nozzle directly acts on the suction port of the electric submersible pump. The present invention can automatically clean the suction port of the electric submersible pump by relying on the pressure difference between the outlet and the suction port of the electric submersible pump.