Abstract: The mineralization,immobilization and priming effect of soil N in raw loessial soil,garden loessial soil and Swedish cultivated meadow soil were studied by using the incubation method with adding glucose-14C,straw-14C,NH4-15N and NO3-15N.The main results obtained were as follows: 1) The added C and N could stimulate the mineralization,immobilization and priming effect of soil N.2) The intensity of stimulation by added C and N was added NH4-15N added NO3-15N,added glucose plus NH4-15N added glucose plus NO3-15N,added straw plus NH4-15N added straw plus NO3-15N, and added glucose plus NH4-15N added straw plus NH4-15N,added glucose plus NO3-15N added straw plus NO3-15N. 3) The priming effect in impoverished soil was higher than that in fertile soil.The concepts of priming effect of soil net mineralization N,priming effect of soil immobilization N and total priming effect of total soil mineralization N were put forward in this paper.It was considered that the total prime effect of total soil mineralization N could reflect the nature of priming effect of soil N.