Abstract: Effect of continuous cropping on the soil enzymes of Ⅰ-107 (Populus×Euramercana 'Neva') poplar nursery was studied. The correlation between soil enzymes, soil nutrients and soil microbes were analyzed. Result showed that wth the planting generations added, activity of urease, catalase and peroxidase of 2nd and 3rd generation decreased by 7.84% and 33.26%, 1.56% and 10.94%, 16.25% and 21.15%, respectively. Compared with the 1st generation, with soil depth increasing, the activities of urease, catalase and peroxidase decreased steadily. But the polypHenol oxidase activity was high in topsoil and lower in deep soil. The correlation coefficients between urease and peroxidase, urease and catalase were significant at 0.05 and 0.01 level. Beside Zn, Mn and Fe, all the other mineral elements, such as available N, P and K and trace-element Cu in soil of 2nd and 3rd generations, were descending by 9.19% and 33.50%, 29.53% and 43.91%, 22.06% and 44.48%, 11.37% and 46.85%, respectively, comparied with 1st generation. Soil organic nutrient contents of 2nd and 3rd generations were decreasing by 15.05% and 29.61%, respectively. Beside polypHenol oxidase enzyme and trace-element Zn, Mn and Fe, correlation between soil enzymes and soil nutrients was significant at 0.05 or 0.01 levels. With the planting generation increasing, the quantity of the soil bacterium, fungi and actinomyces decreased steadily. Total microbe quantity in 2nd and 3rd generations decreased by 29.55% and 52.44%, respectively. Therefore soil bacterium, fungi and actinomyces quantity decreased by 30.10% and 51.88%, 19.91% and 68.39%, 20.17% and 57.18%, respectively. Correlation coefficients between urease and actinomyces, catalase and bacteria, actinomyces, total microbe quantity, peroxidase and fungi were significant at 0.05 levels, and correlation coefficients between catalase and fungi peroxidase and bacteria, total microbe quantity were significant at 0.01 level.