The influence of earthworm activities on the number of soil bacterial physiological groups and enzyme activity was investigated in an agro-ecosystem during the wheat growth season of a maize residue amended seven years rice-wheat rotation. Experimental plots in the rotation had five treatments, i.e. incorporation or surface-application of maize residues with or without earthworm inoculation and a control. The application of maize residues to soil gave higher number of ammonifiers, nitrogen-fixing bacteria, cellulose-decomposing microbes, inorganic phosphorus-decomposing bacteria and significantly higher activities of soil enzyme than control soil. The inoculation of earthworms in maize residue surface-application had higher the numbers of four bacterial physiological groups than the same treatment without earthworms, while the inoculation of earthworms in maize residue incorporation had higher the number of ammonifiers and inorganic phosphorus-decomposing bacteria and significant（P<0.05）increase in soil protease and invertase activities compared with the same treatment without earthworms. The numbers of four soil bacterial physiological groups and four soil enzyme activities in earthworm casts were significantly（P<0.05）higher than those in the surrounding soil. Earthworm activity further increased soil microbial numbers and enzyme activities in crop residue amended agro-ecosystem, which was very important in improving soil fertilization.