Objective To observe the clinical efficacy and safety of the GHA priming regimen of ultra-low-dose decitabine combined with hypertriglyceridin (HHT), cytarabine (Ara-c), and granulocyte colony-stimulating factor (G-CSF) in the treatment of refractory and relapsed acute myeloid leukaemia (AML). Methods A retrospective analysis was performed from January 2018 to August 2023 in our hospital involving 28 patients with refractory and relapsed AML received 2 courses of ultra-low-dose decitabine combined with GHA priming regimen (specifically: decitabine 10 mg/d, intravenous drip, d1-5; HHT, 1 mg/d intravenous drip, d1-14; Ara-c, 10 mg, q12h, subcutaneous injection, d1-14; G-CSF, 300 μg, subcutaneous injection, d0-14), and the therapeutic effects and adverse reactions were evaluated. Results A total of 17 patients achieved complete remission (CR) (60.7%) and 6 achieved partial remission (PR) (21.4%) after 2 courses of treatment, with an overall effective rate (ORR) of 82.1%. Grade IV myelosuppression occurred in 26 patients (92.9%), with a neutrophil deficiency of 85.7% (24 patients), with a mean duration of 7 days (3 - 14 days); platelets ＜20×109/L were 89.3% (25 patients) with a mean duration of 8 days (5 - 17 days). The non-haematological adverse effects were mild and no early deaths occurred. Conclusion Ultra-low-dose decitabine combined with GHA priming regimen for the treatment of refractory and relapsed AML has a high remission rate and is well tolerated, which is worthy of promotion and application