Abstract：This paper studied the effects of microorganism population in continuous and rotated cropping on cucumber seedling growth and soil enzyme activity. The results showed that in rotated cropping microbial treatment，the fresh weight，chlorophyll content，the activities of neutral phosphatase and invertase of cucumber seedlings were significantly higher than that in continuous cropping microbial treatment. Both the continuous and rotated cropping microbial treatments had increased the fresh and dry weights，chlorophyll contents，total leaf area of cucumber seedling，and significantly increased the activities of soil neutral phosphatase，invertase，urease. Summing up the above，soil microorganism population in both cropping systems had a positive effect on the growth of cucumber seedling，and the positive effect on soil microorganism population in rotated cropping was stronger than that in continuous cropping.
