Abstract: This paper reports the first case of myelodysplastic syndromes combined with myeloid sarcoma for which the department of radiotherapy used total marrow and lymphoid irradiation (TMLI) to assist in myeloablating. Radiotherapy localization and target area delineation were carried out before treatment and the entire process of TMLI treatment was designed using the TOMO therapy. Radiotherapy was performed successfully for targeted irradiation of the total bone marrow and lymph nodes. The patient felt comfortable during the treatment process and good pretreatment effects were achieved. The treatment time (45 min-1 h per session) was significantly shorter than that during total body irradiation (TBI)(3-4 h per session), the irradiation dose rate (800 cGy/min) was significantly increased compared to TBI (5-30 cGy/min), and oral mucosal inflammation and gastrointestinal reactions were mild after treatment. This article discusses the treatment process of this case and TMLI technology, to provide reference for the whole process design and important parameters for further treatment of more patients.