Abstract:The soil samples were collected from banana orchard in Hainan island. The distribution of soil aggregates and enzyme activities were analyzed, after cultured in various environment such as drouth, wet, acidification and pathogen invasion (Fusarium oxysporum). The soil aggregates (> 2, 2-0.25, 0.25-0.053 and < 0.053 mm) were separated by wet sieve method. The results showed that the proportion of water-stable macroaggregates (>0.25 mm) significantly decreased, except for the >2mm macroaggregates undergoing acidification. In contrast, microaggregates (< 0.25 mm) increased significantly in all the treatments, compared with the control. In addition, activities of soil invertase, urease, phosphatase and catalase were reduced by 20%-90%. Furthermore, the populations of bacteria were also significantly reduced. After acidification and pathogen invasion, the numbers of F. oxysporum were significantly increased from 102 CFU/g to 103 CFU/g and 104 CFU/g respectively. The analysis of soil DNA indicated that soil microbial community structure was significantly changed after drouth, wet, acidification and pathogen invasion treatments. This study showed that adverse environmental factors seriously affected the soil quality, e.g., aggregate formation and soil enzyme activities.