Abstract: The investigation was carried out to explore the effects of the microbial fertilizers on lettuce soil microorganism and enzymic activity using the soil of planting lettuce as test materials, ten treatments were set up. The soil was sampled to analyze microorganism quantities and enzymic activity at harvest. The results showed that amounts of bacteria and actinomycetes in the soil of all treatments were more than CK; The number of fungi in all treatments were less than CK, and the effect of treatment of application of compound microbial bacterial manure in 1 200 kg/hm²+microbial inoculum（concentration 1∶200）（M2Y2） was the most obvious, followed by the treatment of application of compound microbial bacterial manure in 600 kg/hm²+ microbial inoculum（concentration 1∶200）（M1Y2）, which amounts of bacteria and actinomycetes of the treatment M2Y2 and M1Y2 were increased by 58.81%, 63.93% and 117.55%, 95.91% than CK, their number of funigi were decreased 68.98% and 65.56% than CK, respectively. The soil urease and invertase and the catalase activity of the treatment M2Y2 were the highest, M1Y2 was the second, the treatment of application of compound microbial bacterial manure in 1 800 kg/hm²+microbial inoculum（concentration 1∶200）（M3Y2） was the third, and their enzymic activities were significantly higher than CK, but the enzymic activities of other treatments higher than CK or lower than CK. Only when the ratio of bacterial fertilizer and fungicide was suitable（concentration 1∶200）, the promotion effect on the enzyme activity was the best.

Key words: microbial fertilizer, microbial inoculum, lettuce, soil microorganism, soil enzymic activity