As a new extraction technology, subcritical fluid extraction has received more and more attention, due to its high efficiency and quality. The paper first introduces the basic principle of subcritical fluid extraction, and analyzes the effects of extraction solvent, temperature and pressure, time and frequency, and volume of solvent on the extraction efficiency. Furthermore, the kinetics and thermodynamics of the subcritical fluid extraction process are explained. Then, the quality of the oils obtained by subcritical fluid extraction and other extraction techniques is compared, indicating the migration of bioactive concomitants in the subcritical fluid. Finally, the future research direction of subcritical fluid extraction theory is prospected.