Abstract: The ultrasonic cleaning process of electromechanical product parts is investigated using finite element simulation and orthogonal experiments. The harmonic response of the ultrasonic transducer arrangement on the bottom plate of the cleaning tank is analyzed with ANSYS software, and the configuration of the triangular array is determined. The acoustic field distribution in the cleaning tank is analyzed with COMSOL and the optimal workpiece cleaning station is determined.The ultrasonic cleaning process for different materials and contaminants is investigated through comparative tests. Surface cleanliness of workpieces after ultrasonic cleaning is 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: a temperature of 55 ℃, a power of 0.4 W·cm⁻², and a time of 4 min. Similarly, the optimal process parameters for descaling cleaning are as follows: a temperature of 75 ℃ and a power of 0.4 W·cm⁻². Ultrasonic cleaning process proves 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 test results of water contact angle and spectroscopy 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.