Objective:To develop the quality grading standard of Polgala tenuifolia seedling,and provide a basis for seedling breeding and good agriculture practice of P. tenuifolia. Method:Twenty-seven samples of P. tenuifolia seedling were collected from the main producing area in China and then cultivated in the cultivation base. Fresh weight per plant,dry weight per plant,seedling length,seedling diameter,root length,root diameter,leaf length and leaf width were accurately measured to determine the main indexes for quality grading of P.tenuifolia seedling. K-mean cluster method was used to classify the seedling grading and develop grading standards. Meanwhile, the contents of main active constituents of P. tenuifolia seedling were determined by high performance liquid chromatography(HPLC). Result:Root length,root diameter,seedling length and seedling diameter were the main indexes to evaluate the grading quality of P. tenuifolia seedlings. The fresh weight per plant was an important index to evaluate the quality of P. tenuifolia seedlings,whereas the leaf length was the reference index. Combined with the production practice of P.tenuifolia, P. tenuifolia seedlings from different origins were divided into three grades:the criteria of the grade 1 seedling were as follows:single plant fresh weight ≥ 0.18 g,root length ≥ 12.00 cm,root thick ≥ 0.10 cm,and seedling length ≥ 14.00 cm;the criteria of the grade 2 seedling were as follows:single plant fresh weight 0.10-0.18 g,root length 9.00-12.00 cm,root thick 0.07-0.10 cm,and seedling length 12.00-14.00 cm;the criteria of the Grade 3 seedling were as follows:single plant fresh weight 0.08-0.10 g,root length 8.00-9.00 cm,root thick 0.06-0.07 cm,and seedling length 10.00-12.00 cm. Conclusion:Seedling is the basis to ensure the medicinal quality,so it is recommended to use grade 1 seedling and grade 2 seedling in the artificial cultivation of P. tenuifolia to obtain high output and high quality P. tenuifolia.