Abstract: 【Objective】 This project aims toclarify the action characteristics of the new biological herbicide Thaxtomin A (TA) in Convolvulus arvensis L. and Abutilon theophrasti Medicus.Finding from which provides a research basis for the practical application of TA. 【Methods】 The effects of different environmental factors (temperature, humidity and rainfall after application) and soil factors (soil organic matter content and soil pH) on the herbicidal activity of TA against Convolvulus arvensis L. and Abutilon theophrasti Medicus were studied by indoor bioassay method. 【Results】 The results showed that at 35℃ / 30℃, 50% humidity, soil pH = 9 and high organic matter content, TA had the best control effect on Convolvulus arvensis. However, 0.5 h rainfall after application would significantly reduce the control effect and should be sprayed again. At 30℃/ 25℃, 70% humidity, soil pH = 8.0, and low soil organic matter content, TA had the best control effect on Abutilon theophrasti. Rainfall within 1 h after application would reduce its control effect, and appropriate amount of pesticide should be applied. 【Conclusion】 Different climatic factors and soil factors have significant effects on the efficacy of TA, At the same time, for different weeds, the changes of environmental factors have different effects on the efficacy of TA. Different temperatures,humidity,duration of light exposure,rainfall after pesticide application,soil organic matter and soil pH value has a certain impact on the herbicidal activity of TA.