Abstract：Literature research and analysis of Paeonia Lactiflora in Baoyin Jian in Jingyue Quanshu was carried out by taking the effect of “Shaoyao” in Baoyin Jian，the medication habits of ZHANG Jingyue in treating yin deficiency，and the use of Baoyin Jian by physicians in past dynasties as the entry points. It is inferred that the Paeonia Lactiflora used in Baoyin Jian is “Paeoniae Radix Alba”，and the reasons are as follows： there are records that “Radix Paeoniae Alba” was used in the prescription for treating yin deficiency syndrome in Jingyue Quanshu(The Complete works of ZHANG Jingyue)； many medical books recorded the use of “Paeoniae Radix Alba” by physicians of various dynasties using Baoyin Jian，whose scope of treatment basically inherited Jingyue's theory，and the prescription was mainly used to treat the syndrome of yin deficiency with internal heat and bleeding.