We studied the dry weight of individual plant,nitrate reductase activity and mineral elements absorption of leaves under three nitrogen forms and different concentration ratios by the use of orthogonal design,which were ammonium nitrogen,nitrate nitrogen and the amide nitrogen.The results showed that:(1)There were different dry weights by different nitrogen forms,which amide nitrogen was the most important nitrogen form,followed by ammonium and nitrate nitrogen;(2)There were different nitrate reductase activities in leaves by different nitrogen forms,which ammonium nitrogen was the most important nitrogen form,followed by nitrate and amide nitrogen;(3)The combined application of different nitrogen forms can promote absorption of phosphorus P,potassium K,calcium Ca,Mg,Cd,manganese Mn,chromium Cr,strontium Sr elements,but it is not beneficial to the absorption of nickel Ni,and iron Fe.Seven mineral elements,which were affected the most significantly by ammonium nitrogen,were K,Ba,Se,Ni,B,Si and Fe.Five elements,namely P,Cd,Ti,Al and Cu were affected the most significantly by nitrate nitrogen,and Na,Ca,Mg,Zn,Mo,Mn,Cr and Sr elements were affected by amide nitrogen.There were obviously differences among the effect of mineral elements absorption by different nitrogen forms.We should focus on the construction of the morphogenesis in the seeding stages of Isatis indigotica,and pay more attention to the combined application between the amide nitrogen and inorganic ammonium nitrogen,nitrate nitrogen.The appropriate nitrogen forms and ratios can increase nitrate reductase activity and promote minerals elements absorption,thereby promote the growth of I.indigotica.