Abstract: Researching progress of several key factors that maize gene transformation using Agrobacterium tumefaciens were reviewed，including explant，base-medium and supplementary, co-culture temperature，signal molecular and Vir gene activation。Research found that immature embryos are the optimical explants especially when it is from 1mm to 2mm , the co-culture temperature from 200C to 250C. Research demonstrate that the barrier of transfer the foreign gene to the gramineous plants using Agrobacterium tumefaciens is lack phenol and it is difficult to induce the Vir gene activity.So supplementary the acetosyringon in co-culture medium was essential to efficient transfer foreign gene to gramineous plants. Besides, a high incidence of T-DNA transfer was also closely associated to the supplementary such as organic nitrogen , amino acid and metal ions.