Objective To study the change of the transfected efferency of GFP gene by transfecting plasmids inserted different segments with different amounts.Methods The plasmids inserted different segments were constructed and transfected into HeLa cells with different transfected condition,Northern blot then was used to detect the expression of the transfected plasmids respectively.Results The transfected efficiency of the cell concention of 2.0×105/mL was higher than that of the cell concention of 1.0×105/mL;When the ratio between the plasmid and the lipofectamine was kept constantly,the transfected efficiency increased with the amount of the transfected compound increase.When the amount of lipofectamine was constantly,the transfected efficiency of C1-ORF2,C1-ORF2as,and C1-280-1×14 as firstly increased then decreased or kept fair with the transfected amount increased.Conclusion The type and amount of transfected plasmids and the concentration of transfected cells influenced the expression of transfected plasmids.