Abstract: ob＜x＞jective To compare the efficacy of decitabine combined with CAG regimen (cytarabine + acramomycin + granulocyte colony stimulating factor) and PD-1 inhibitor (tirelizumab) combined with decitabine combined with CAG in the treatment of relapsed/refractory acute myeloid leukemia (AML). Methods fifty-eight patients diagnosed with relapsed/refractory AML in our hospital from January 2018 to October 2021 were enrolled, including decitabine combined with CAG (D-CAG) group (n=40),?PD-1 inhibitor combined with decitabine combined with CAG (PD-CAG) group (n=18), OS, complications, biochemical indicators and prognosis of the two groups were compared.?Results There was no statistical difference in CR rate between D-CAG (15.7%) and PD-CAG (16.7%), and no statistical difference in median OS survival and median progression-free survival (PFS). The 1-year OS rate in PD-CAG group (72.72%) was higher than that in D-CAG (45.32%).?The total OS curve showed that the prognosis of PD-CAG group was better.?In the PD-CAG group, elderly patients > 60 years old had higher PFS, and the incidence of myelosuppression was lower in the PD-CAG group than in the D-CAG group.?Conclusion Compared with D-CAG regimen, PD-CAG regimen may improve the overall prognosis of patients and reduce the occurrence of myelosuppression, but there is no significant difference in CR rate between the two regimen. PD-CAG regimen provides a possible option for the treatment of AML.