Abstract: The experiment was conducted to study the variation of soil nutrient，enzyme activities and microorganism category in the soil of 2-year Newhall Navel orange（Citrus sinensis Osbeck‘Newhall Navel’）seedlings，planted in pots at different managements by clean tillage，sod culture and intercropping green manure. The results showed that the contents of soil organic matter，total N，available K and P were obviously improved by intercropping green manure and sod culture，but the available N content in the sod culture soil was lower than that of clean tillage. Compared with the control，the activities of the urease，protease and catalase of green manure and sod culture treatment were improved obviously. The bacteria quantity in the soil，ranked first，account for 90 percent of total microorganisms during the whole growing period of the seedlings，and then were the actinomycete and fungi. The quantity of soil bacteria andactinomycete were improved，while the fungi quantity was improved by sod culture. Further analysis showed that there is significant positive-correlations between the enzyme activities，the microorganism quantity and the soil nutrients.

Key words: Citrus, soil management, soil nutrient, enzyme activity, microorganism