Due to its ability to form dense mats in small water bodies (such as rivers and landscape ponds), duckweeds are often considered as nuisance plants in some freshwaters. As an attempt to find a new effective management tool, this study set out with the aim of assessing the influence of seven Chinese herb extracts addition upon the growth of duckweeds (Soirodela polyrhiza). The results show that Coptis chinensis Franch, Euphorbia humifusa willd and Alisma plantago-aquatica extracts have significant growth inhibition on Soirodela polyrhiza. Coptis chinensis extract showed statistically significant effect on Soirodela polyrhiza frond growth with few new fronds found after 96 h. Euphorbia humifusa extract increased Soirodela polyrhiza biomass slower than that of the control. Accounting for 69% of control was found after plants received the extract 96 h. Alisma plantago-aquatica extract showed statistically significant effect on Soirodela polyrhiza chlorophyll. Compared with control, higher than 55% chlorophyll decrease was found after plants received the extract 96h. In conclusion, Chinese herb extracts can inhibit the growth of extract and effectively controlled Soirodela polyrhiza growth. This study suggests that using Chinese herb extract as an herbicide to control the blooms of duckweeds is workable.