Alligator weed（Alternanthera philoxeroides）is a menace to the environment and due to its invasive nature,it has the potential to threaten the aquatic flora and fauna since it has a deleterious effect on water quality and water flow.Although there are many factors that causers stress on the alligator weed,light and water stress are the most important environmental factors that inhibit the growth of the weed.In light stress study,alligator weed plants were divided into 6 groups exposing to different light intensities from 0%（total darkness）to 100%to the natural light.Results showed that the biomass（stem,leaf and roots respectively）,leaf area,and leaf size showed a declining trend with a reduction in light intensities,while the height of the plant showed an inversed relation with light intensity.In water stress study,the growth of stolon alligator weed was examined in 11 groups and was exposed to different water supply conditions from 0 irrigation to 1000 ml per pot per week.Results suggested that when the water supply less than 500 ml per week per pot（with a land area of 0.04m2）,alligator weed is unable to survive.Water less than 700ml/pot was lower than the plant requirement and thus its growth was inhibited.when the water quantity was increased to 700ml to 1000ml/pot,the plants showed growth and it survived.The study indicts that the spreading of Alligator weed can be controlled by reducing water supplies.When the alligator weed grows in water bodies,it could be controlled by providing shade in that areas.