Abstract:In this study, the characteristics of soil microbial biomass and enzyme activities of bamboo and broad-leaved forests with different mixed ratios (0-10%, 10%-20%, 20%-30%, 30%-40%, and above 40%) were investigated in order to evaluate the effect of mixed ratio on soil conditions. Three sample plots (20 m ? 20 m in size) were set for each ratio, and soils of 8 sampling points were randomly collected in S-shape within each plot in December 2017. The results showed that the mixed ratio and soil depth significantly influenced soil microbial biomass nitrogen (SMBN) and enzyme activities, but influenced insignificantly soil microbial biomass carbon (SMBC). SMBC, SMBN and enzyme activities decreased with the increase of soil depth. SMBC was the highest (357.67 mg/kg) in the mixed ratio of 30%-40%, SMBN was the highest (127.00 mg/kg) in the mixed ratio of 20%-30%. The activities of soil urease, sucrase and catalase were higher in the mixed ratio of 20%–30%, while were the lowest in the mixing ratio of 10%-20%. Correlation analysis indicated that the activities of soil urease, sucrase and catalase were positively correlated with SMB, among of which, the activities of soil catalase and urease had significant positive correlation between SMBC and SMBN, while the activities of soil sucrase and catalase were significantly correlated with SMBN. SMBC was significantly positively correlated with pH and total nitrogen. There was a very significant positive correlation between SMBN and soil water content and total nitrogen. The activities of soil urease, sucrase and catalase were positively correlated with soil organic carbon, total nitrogen. In conclusion, the mixed ratio, soil depth could impact on SMBC, SMBN and enzyme activities significantly, the mix ratio has a certain impact on soil conditions, and the mixed ratio of 20%-30% has the best soil microbial status.