Objective: In order to substantially know the weeds community and its characteristics in cotton field under mulch-drip irrigation of the south Xinjiang, an investigation on weeds was conducted. Finally a theoretical base of weeds control was provided in cotton subregions of the Southern prematurity and medium ripening taha. Method: Laid heavy stress on the years of cotton field with drip irrigation in townships of Avati County, weed community and quantities were investigated, including comparing with weeds community under the different mode of cotton. Result: There were a lot of weeds species in different cotton mode, including 9 families 15 kinds. Their main species were gramineous, compositae and chenopodiaceae families which had great effect on cotton growth. Conclusion: Compared with cotton fields under outdoor sowing, conventional irrigation and mulch-drip irrigation, the dry weight of weeds root hade significantly lower. The reason was that enough water and nutrient were supplied in time in cotton field under mulch-drip irrigation. The weeds quantity of annual shallow roots and broad-leaved had tendency to increase. The weeds had two harm peaks in the cotton growth period, and peak harm appeared earlier and continued for longer time.
