Abstract：This paper introduces Professor JI Yunxi's clinical experience in differentiating and treating infertility by applying the yang-reinforcing and yin-expelling method. Professor JI Yunxi holds that the core pathogenesis of infertility is yang deficiency and yin excess. Therefore，he proposes that the yang-reinforcing and yin-expelling method serves as the fundamental treatment for infertility. "Yang reinforcement" aims to support yang qi，with supplementing kidney yang as the foundation，warming spleen yang as the adjuvant，and reinforcing heart yang to calm ministerial fire as the principle. "Yin expelling" refers to eliminating pathogenic factors（predominantly yin pathogens），emphasizing the transformation of yin into yang. It mainly focuses on dispelling cold-damp，while also addressing other stagnant pathogens such as phlegm-damp，blood stasis，and qi stagnation. In clinical practice，the balance of yin and yang is carefully assessed，addressing both the root and the branch to warm the uterine cavity for qi-blood generation，unblock the uterine cavity to eliminate cold-damp，and achieve yin-yang harmony for successful conception.