Abstract: Abstract: 【Objective】 To improve the yield and quality of Pseudostellaria heterophylla and provide a theoretical and practical basis for high-yield cultivation of P. heterophylla, the effects of NAA(naphthalene acetic acid)on the growth and active ingredients in the root tuber of P. heterophylla seedlings were explored.【Methods】After treatment with different concentrations NAA(CK, 10, 20, 50 mg/L), growth indexes and the contents of active ingredients of P. heterophylla were determined. The contents of saponin, trace elements and amino acids were measured by HPLC, ICP-OES and a high speed amino acid analyzer, respectively. 【Results】The results showed that the appropriate concentrations of NAA could significantly increase root tuber yield and active ingredient contents of P. heterophylla. The treatment with 10 mg/L concentration had the best effect. The dry and fresh weight of root tuber yield per unit area, and saponin yield, significantly increased by 39.88%, 39.36% and 60.69%, respectively, compared with that of the control. The contents of the mineral elements Fe, Mn, Zn, Co and Se were the highest with the concentration of 10 mg/L NAA, except for Cu, and were significantly higher than that of the control. However, the maximal increase in human constant elements Ca and Mg was attained with the 50 mg/L treatment. NAA treatments could increase contents of various amino acids in the root tubers of P. heterophylla by different degrees. The contents of total amino acids and medicinal amino acids were the highest for the 10 mg/L NAA treatment and significantly increased by 39.77%, 43.42%, respectively, compared with that of the control. 【Conclusion】The application of the appropriate concentrations of NAA were effective in increasing root tuber yield and active ingredient contents of P. heterophylla, improving its quality. Correlation analysis revealed relationships between saponin content and the contents of Fe, Co, Se, threonine, and other amino acids were significantly positive.