This paper presents the results of studies on evaluating the effectiveness of wastewater treatment by Eichhornia crassipes raft, the influent is the water of To Lich river. This study was conducted 3 times with 3 different velocity (0.037 m/s, 0.0099 m/s and 0.0126m/s) in the tank of eichhornia crassipes. Each time took 04 water samples for analysis at 4 locations: the influent source and 3 points at a distance of 4.0 m, 8.0 m and 12.0 m from the influent. Based on the experimental results, it proposes the size, number and type of raft to control the growth of eichhornia crassipes and treat the sewage of To Lich river to meet the Vietnamese Water Standard QCVN 08 (column A2, B1) and combine ecological landscaping.