For the environmental quality evaluation of vegetable bases standards uncertainty,the paper applied the unascertained cluster method to the environmental quality evaluation. In the paper it selects soil environmental quality of six township of Liuhe district,Nanjing city,Jiangsu province as the research objects. Taking "China's soil environmental quality standard"as evaluation criteria,and selecting six common pollutants as evaluation factor,such as Cd,Hg,As,Cu,Pb,Cr. The environmental qualities comprehensively based on the measured data of Jiangsu province in the experiment were assessed. At last,six samples of soil environmental quality were divided into clean,light pollution and severe pollution. And the class centre,subjection degree and classification results were obtained. Experimental results show that the classification result is consistent with actual situation and the method applied to the vegetable origin in environmental quality assessment is feasible.