Effects of earthworms on soil mineral N were studied through lab incubation and long-term field experiment.It was found that earthworm greatly influence the NH₄⁺-N,NO₃^--N and NH₄⁺-N + NO₃^--N,and promoted the soil mineralization.In field experiment,NO₃^--N and NH₄⁺-N + NO₃^--N were significantly increased by earthworm in rice season of 2001 and in wheat season of 2003.However,there were no signification effects in other harvest season.In the labincubation experiment,the role of earthworm on soil mineralization was distinct.Especially in without cornresidues treatments,NO₃^--N,NH₄⁺-N + NO₃^--N,Cumulative N Mineralization and Net Mineralization Rate were all significantly increased by earthworm incubation.