Abstract: Abstract:To examine the spatial changes of microbial metabolic activity in an iron mine upstream from Miyun Reservoir, the microbial activity and microcalorimetry heat metabolism activity index were applied in the method of calorimety and microcalorimetry from different sample sites. The results showed that:w(Cu), w(Cd), w(Zn) and w(Cr) of different soil sampling sites were higher than the Beijing local soil background values. In samples with relatively low degree of heavy metal pollution (S6, S7 and S8), the urease activity was 0.64,1.22 and 0.64 mg/g, and the FDA enzyme activity was 1.25,2.84 and 1.45 μg/g, respectively, higher than other points. The microcalorimetry heat metabolism activity index showed that, in light pollution, the constant growth rate of k was very high, while in seriously contaminated sites S1 and S2, the k values approached zero. Correlation analysis showed that k was the most representative index to trace the metabolic heat activity. The RDA results indicated that w(Cd), w(TN), w(AP), w(TOC), Nemerow and w(Cu) were identified to be the major influential environmental factors driving changes occurring in the metabolic activity k, FDA, urease and P_m. The microbial metabolic activity was inhibited by Cd and Cu. k was the metabolism activity index most sensitive to heavy metals, while P_m, urease activity and FDA enzyme activity took second place.