To understand the effects of herbicides stress on the population of Alligator Weed Flea Beetles, Agasicles hygrophila and find corresponding strategies that are herbicides applcation correctly and protection A. hygrophila effectively against herbicides which would improve the biological control for alligator weed, Alternanthera philoxeroides, The hatching rate of eggs, survival percentage both larvae and adults and eclosion rate of pupae of A. hygrophila against herbicides stress, which were glyphosate, Roundup, 14% metsulfuron CFC imidacloprid EC and 35% benzyl. Ding WP stresses, were tested by the leaf residue method. The results showed that 4 kinds of herbicides mentioned above decreased the hatching rate of eggs, survival percentage of both larvae and adults and emergence rate of pupae of A. hygrophila at some way. Specially, the hatching rate of eggs falled significantly against 14% metsulfuron CFC imidacloprid EC of the 28.0,35.0 g/Lconcentrations and 35% benzyl. Ding WP of 4.0 g/Lconcentrations stresses; The survival rate of both 1^st and 3^rd larvae in early stage droped markedly under Roundup of concentrtion 13.4 g/L and 14% metsulfuron CFC imidacloprid EC of concentrtion 28.0 g/L stresses. A marked decline on the survival rate of 2^nd instar larvae in later stage was observed in Roundup of the concentrtion 40.1 and 53.4 g/L stresses. Glyphosate which tested concentration were both 97.6 and 122.0 g/L, Roundup which tested concentration were both 26.7 and 66.8 g/L and 35% benzyl. Ding WP which tested concentration was 2.0 g/L suppressed obviously the emergence rate of pupae in later stage of A. hygrophila. The survival rate of female adults after 3 days eclosion was decreased significantly under 35% benzyl. Ding WP of 1.0 g/L concentration stress. It expressed the information that herbicides could decreased the number of the population by killing the indiviuals of A. hygrophila directly and could destroy the population of leaf beetles quickly by damage their comestible host plants and habitats in short time. It is suggested that herbicides should be equitable application and recommend keeping some small patches free from herbicides to protect A. hygrophila. It is hopeful to improve the biological control effect of A. hygrophila on alligator weed.