Recent studies have found that intestinal flora dysregulation may be closely related to the pathogenesis and progression of Parkinson’s disease (PD). Whether in the preclinical, early, middle and late stages of PD, the regulation of intestinal flora may bring new opportunities to the treatment of PD. The correlation between intestinal flora dysregulation and the pathogenesis of PD coincides with the theory of syndrome differentiation and treatment based on spleen by the stages of PD, which is developed by Professor CAI Gan—an inheritor of CHENG Menxue’s academic thoughts inherited from DING’s internal medicine of traditional Chinese medicine. Based on this theory, syndrome differentiation and treatment with the classical prescription revised on a small quantity based on spleen by stages of PD can achieve satisfactory results, which provides empirical evidence for the treatment of PD and other neurodegenerative diseases with the integration of traditional Chinese and western medicine.