A laboratorial incubation experiment was conducted to test the response of earthworm (Eisenia fetida)-related microbes to the application of dicyandiamide (DCD), a nitrification inhibitor. The potential of ammonium oxidation in soil was inhibited during the 90 days cultivation. At day 90, it was observed the soil surface was drilled more severely by earthworms in DCD treatment than E treatment. Meanwhile, comparedwith E treatment, the results of soil community level physiological profiles indicated that the potential of carboxylic acids and carbohydrates utilization in soil was enhanced by DCD addition.The active microbial biomass was increased by 43% andthe polyphenol oxidase activity was enhanced by 14% in DCD treated soil than control. More importantly, the number of denitrifying bacteria in earthworm gut content at day 90 was markedlydeclined from 1.79×10¹⁰g [fresh wt]^-1 in control to less than 1×10⁶ g [fresh wt]^-1in DCD treatment.These results implied that DCD application was anabiotic selection pressureon the activities of earthworms and themicrobes both in soil and in earthworm, which might led to a shift of interaction between earthworms and the microbes.