The pot culture experiment was conducted to study the effect of different nitrogen forms and ratios on the nitrate and nitrite accumulation and quality of Platycodon grandiflorum. The results showed that:(1) When NH⁺₄N/NO^-₃N was 25∶75, the contents of nitrate and nitrite reached their minimum values.The nitrate accumulation increased constantly during the cultivation process of P. grandiflorum.In contrast，while the nitrite accumulation decreased during the cultivation process of P. grandiflorum.(2) The content of Vc was the highest at the NH⁺₄N/NO^-₃N ratio of 0∶100. And the contents of soluble protein, amino acids,Fe,Mg,Cu were the highest at the NH⁺₄N/NO^-₃N ratio of 75∶25.(3) The contents of N,Cu,Mn and Zn had their maximum values under amidenitrogen treatment.(4) The total flavonoids content decreased with the increasing of NO^-₃N. At the NH⁺₄N/NO^-₃N ratio of 25∶75, the platycodin contents and polysaccharide contents of P. grandiflorum reached its maximum values. Studies had shown that: proper application of different nitrogen forms decreased the nitrate and nitrite contents and increased the quality of P. grandiflorum and the best treatment was the NH⁺₄N/NO^-₃N ratio of 25∶75. It was worth noting that nitrogen fertilizers should not be used before the harvest time of P. grandiflorum.