Dai?蒺s theory of meridian sinew is one of the important part of dai medical theoretical system, in the Dai national minority area is widely applied in clinic diagnosis and treatment of disease process. Lumbar and dorsal myofasciitis， a common clinical disease, belongs to the category "low back pain" in Dai medicine, and close to the reinforcement. The author based on meridian and sinew theory of Dai medicine to explore the etiology and pathogenesis of lumbar and dorsal myofasciitis, think that the lumbar and dorsal myofasciitis due to internal and external factors, like "attacks" and "inadequate" of four tower, ultimately affect the operation of qi and blood in the small of the back. Using Dai medical treatment, such as lamented muscle therapy and stepping back therapy, follow the human body by the meridian and sinew in a particular technique to operate, can dredge meridians and relieve pain effectively. To explore the existing mechanism and application mode of meridian and sinew theory of Dai medicine in the diagnosis and treatment of lumbar and dorsal myofasciitis is of far-reaching significance for improving the meridian and sinew theory system and promoting the diagnosis and treatment technology of Dai medicine.