A ternary mixed metal oxide coating of Sn−Ru−CoO x was prepared by ultrasonic treatment. The effect of ultrasound on the electrochemical performance and corrosion resistance of the electrode was investigated in this paper. Results showed that the electrode prepared by ultrasonic pretreatment demonstrated more uniform oxide dispersion on the surface of the coating, smaller grain growth, and more compact surface morphology compared with the anode prepared without ultrasonic pretreatment. At the same time, the best electrocatalytic performance was obtained by the ultrasonically treated coating. The chlorine evolution potential was reduced by 15 mV. The anode prepared by ultrasonic pretreatment had a service life of 160 h, which was 46 h longer than the anode prepared without ultrasonic pretreatment.