Ultrasound-assisted extraction coupled with gas bubble flotation was developed as a green method for extracting β-amyrin fromDischidia major. The solvent system was water:ethanol (9:1). To improve the adsorption of β-amyrin onto the air/liquid interface during flotation, surfactants were employed; however, the positive effect was only observed with cationic surfactants. High-performance liquid chromatography with spectrophotometric detection (HPLC-PDA) was, for the first time, applied to quantify the β-amyrin content in D. major and its extracts. With the assistance of surfactants, the foam layer collected from flotation showed high selectivity toward β-amyrin. The product content was notably increased after surfactants had been removed from the solution.