The grey relational analysis was initiated to investigate the relationships between the physiological properties of aquatic plants and the performances of the bio-eco-technology for the treatment of malodorous rivers in Shanghai. The main objective of this research was to provide scientific explanation for the water purification mechanisms of the bio-eco-technology. The results indicated that the priority response order of the plants physiological properties for COD and NH4+ -N removal was POD＞CAT＞Chla＞SP＞Chlb, indicating that the microbial degradation could be mainly responsible for the removal of COD and NH4+ -N. However, the priority associated grade of the plant physiological characteristic for TP removal was Chlb＞SP＞Chla＞CAT＞POD, demonstrating that the adsorption of aquatic plants played a dominant role in removing total phosphrous from malodorous black water.