Removal behaviors of the electroplating masking paint on aluminum alloy surfaces were investigated by utilizing a microwave plasma jet. In this study, the plasma jet's changes in physical and chemical properties were analyzed by a camera and optical emission spectrometer (OES). The paint coating's alterations in weight, morphology, and composition were measured by electronic analytical balance, scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). The results indicate that using a mixed gas of Ar + O2 + CF4 is the ideal way to remove the electroplating masking paint in theory. The paint's organic component can be rapidly decomposed by oxygen plasma, whereas inorganic fillers can only be eliminated slowly via fluorine-based plasma etching. The removal rate of electroplating masking paint greatly depends on the active species' content in the plasma jet. Increasing the microwave power and the oxygen proportion can significantly improve the cleaning efficiency. Considering the residual inorganic filler can hinder the lasting reaction between oxygen plasma and the paint coating, a plasma-ultrasonic method, namely using oxygen plasma to rapidly decompose the paint coating's organic component within the effective cleaning time and then eliminating the inorganic filler by pure water ultrasonic, was proposed to achieve the efficient and thorough cleaning of local electroplating workpieces.