Immune thrombocytopenia (ITP) is a clinically prevalent acquired hemorrhagic disease. Modern medical treatment is prone to recurrence with uncertain long-term efficacy, while combined treatment with traditional Chinese medicine (TCM) shows significant advantages. Based on TCM theory and the understanding of physicians in successive dynasties, the core pathogenesis of ITP is blood heat as the initiating factor, blood stasis as the central link, and healthy qi deficiency as the fundamental basis. These three factors interweave with qi movement disturbance to form a vicious cycle. Accordingly, a syndrome differentiation-based treatment system centered on Liangxue Jiedu Decoction (Cooling Blood and Detoxifying Decoction) is constructed: in the acute phase, clearing heat, cooling blood and detoxifying are adopted to expel pathogenic factors; throughout the entire treatment course, promoting blood circulation to remove stasis and astringent hemostasis are taken into account; for yin deficiency with blood stasis, nourishing yin and promoting blood circulation are used together; in the chronic phase, tonifying qi, invigorating the spleen and controlling blood are implemented. This system conforms to the pathogenesis of ITP characterized by deficient root and excessive branch as well as intermingled heat and stasis, demonstrates the TCM concepts of syndrome differentiation-based treatment and simultaneous treatment of root and branch and provides theoretical support for clinical treatment.