Abstract:〔Abstract〕 Objective To investigate the clinical efficacy of azacytidine combined with all trans retinoic acid (ATRA) in the treatment of medium to high-risk myelodysplastic syndrome (MDS). Methods A retrospective analysis was conducted on 33 patients with medium to high risk MDS admitted to Jiangmen Central Hospital from February 2016 to December 2019 as a control group, who were treated with component blood transfusion, hematopoiesis promotion, and general symptomatic support, and 33 patients with medium to high risk MDS admitted to Jiangmen Central Hospital from January 2020 to January 2023 as an observation group, who were treated with azacitidine combined with ATRA on the basis of the control group. The hemoglobin (Hb), platelet count (PLT), and neutrophil count (ANC) of two groups of patients before and after treatment, as well as the blood transfusion interval, transfusion volume, clinical efficacy, and adverse reactions of the two groups of patients were compared. Results After treatment, the levels of Hb, PLT, and ANC in the observation group were higher than those in the control group, the blood transfusion interval was greater than that in the control group, the blood transfusion volume was less than that in the control group, and the complete remission rate and total response rate were higher than those in the control group, the differences were statistically significant (P < 0.05). During the treatment period, there was no statistically significant difference in the incidence of gastrointestinal reactions between the two groups, the difference was not statistically significant (P > 0.05). The incidence of fever, infection, and bleeding in the observation group were lower than those in the control group, the differences were statistically significant (P < 0.05). Conclusion The combination of azacytidine and ATRA has good efficacy in the treatment of high-risk MDS, which can improve clinical symptoms, prolong blood transfusion intervals, reduce blood transfusion volume, and have high safety.