Taiwanese green propolis is rich in prenylated flavonoids and exhibits a broad range of biological activities, such as antioxidant, antibacterial, and anticancer ones. The bioactive compounds of Taiwanese green propolis are propolins, namely C, D, F, and G. The concentration of propolins in Taiwanese green propolis varies depending on the season and geographic location. Thus, it is critical to establish a standard and repeatable procedure for determining the quality of Taiwanese green propolis. Here, we present a protocol that uses ethanol-based extraction, high-performance liquid chromatography, and an antibacterial activity analysis to characterize Taiwanese green propolis quality. This method indicates that 95% and 99.5% ethanol extractions achieve the maximum dry matter yields from Taiwanese green propolis, thereby yielding the highest concentrations of propolins that have antibacterial properties. According to these findings, the present protocol is deemed reliable and repeatable for determining the quality of Taiwanese green propolis.