Abstract: The ultrasonic cleaning process of electromechanical product parts was investigated using finite element simulation and orthogonal experiments. ANSYS was used to analyze the harmonic response of the ultrasonic transducer arrangement on the bottom plate of the cleaning tank, and the configuration of the triangular array was determined. COMSOL was used to analyze the acoustic field distribution in the cleaning tank and determine the optimal workpiece cleaning station. The ultrasonic cleaning process for different materials and contaminants was investigated through comparative tests. Surface cleanliness of workpieces after ultrasonic cleaning was evaluated using image inspection, water contact angle, and X-ray photoelectron spectroscopy. Experimental results show that the optimal process parameters for ultrasonic oil cleaning are as follows: cleaning temperature of 55 ℃, cleaning power of 0.4 W·cm⁻², and cleaning time of 4 minutes. Similarly, the optimal process parameters for descaling cleaning are as follows: cleaning temperature of 75 ℃ and cleaning power of 0.4 W·cm⁻². Ultrasonic cleaning has a high cleaning efficiency in removing oil and corrosion from the surfaces of 45 steel, 40Cr13 stainless steel, 2Al2 aluminum alloy, and H62 brass. Both the contact angle of water and spectroscopy test results demonstrate that the ultrasonic cleaning process proposed in this paper has a significant impact on removing dirt from the surface of workpieces made of different materials. It meets the cleanliness standards required for most precision electromechanical product parts before assembly.