Abstract: To study the effect of sweetpotato cultivation by herbicides combined with plastic films, three herbicides, including 33% pendimethalin EC, 96% metolachlor EC and 50% acetochlor EC, are combined with mulching to control weed and increase yield in sweetpotato cultivation in poor dryland. The results showed that the average fresh tuber yield and dry yield of six treatments increased by 3.79 and 4 times, respectively, compared with CK, and the average stem leaf yield increased by 0.9 times. Among these treatments, the effect of 33% pendimethalin 4500 mL/hm2 with transparent film was the best; after 30 days and 45 days, the control efficacy on weeds were 87.33% and 85.33%; after 45 days and in the harvest time, the fresh mass efficacy reached 93.98% and 88.1% , respectively. The fresh tuber yield was 30300 kg/hm2, increased by 7 times compared with CK, the dry yield was 9999 kg/hm2, increased by 7.6 times and stem leaf yield was 25200 kg/hm2, increased by 2.7 times. In conclusion, sweetpotato planting benefit is low in poor dryland without taking agronomic measures, spraying herbicides combined with mulching before planting can effectively control weeds, improve soil temperature, promote seedling growth, fertilizer and water conservation, save labor, increase production, achieve the purpose of efficiency. The adoption of pendimethalin with transparent film should be widely promoted for its best effect.