In order to analyze the effect of the attachment of suspended matter on the physiological and biochemical characteristics of macrophyte, several indices were tested: fresh weight (FW), chlorophyll content, net primary production, peroxides(POD) activity and catalaes(CAT) activity. Results showed that high loading suspended matter in Miaojia River in Suzhou had significant effect on the growth of Potamageton crispus. After the experiment was finished, its biomass, chlorophyll content, and ratio of chlorophyll a/b of Potamageton crispus being attached with suspended matter were only 63.93%, 66.24% and 63.88% of the reference one respectively. Activities of POD and CAT of Potamageton crispus decreased, which were 61. 25% and 40. 30% of the reference one. Suspended matter was one of the important factors controlling the reconstruction of submerged macrophyte.