Abstract: The purpose of this experiment is to test the impact of glyphosate herbicide-75.7% glyphosate soluble powder, which is produced by Zhejiang Long You Lv De Pesticide Chemical Plant Ltd. 75.7% glyphosate is a kind of highly efficient contact herbicide and of organic phosphorus herbicide medicine. It has solved the problem of low-content of organic herbicide in water. In the experiment, there are 4 different dosages tests adopted (1135.5、1704.0、2271.0、3406.5g,ai/hm2）and 4 repetitions in each dosage compared with two disposals of which one is adopted with water and the other is sprayed with 75.0% glyphosate soluble powder. Conducted results showed that the lowest mean weeding rate was 97% after thirty days. The rate of effect reached to the peak after fifteen days, among 4 dosages, the effect of a dosage of 3406.5g,(ai)/hm2 is best. So 75.7% glyphosate SG has the following advantages: highly effect in weed control, diffused scope of weed, the high efficiency, and long remaining action, low noxiousness for both animals and people. It is appropriate to weed control by this chemical medicament for 1~2 times in all year in Guangzhou area.