ObjectiveTo investigate the clinical value of small-for-size left lobe liver auxiliary partial orthotopic liver transplantation (APOLT) in the treatment of decompensated cirrhosis. MethodThe preoperative and postoperative clinical data of 4 patients who received small-for-size left lobe liver APOLT in 2023 were retrospectively described and analyzed. ResultsOne patient suffered metabolic liver disease cirrhosis and the other three suffered hepatitis B cirrhosis, all of whom presented with decompensated cirrhosis. Preoperative evaluation showed that the graft-to-recipient weight ratio was less than 0.6%. All recipients underwent left hemihepatectomy. The grafts were derived from living donors in 3 cases, from donation after citizen death in 1 case. After APOLT treatment, 4 patients and grafts survived, 1 patient experienced transplantation rejection and recovered after modified anti-rejection therapy. Three patients with hepatitis B cirrhosis were treated with nucleoside analogues and hepatitis B immunoglobulin, the hepatitis B virus DNA was negative at the end of follow-up, one of three patients with hepatitis B cirrhosis showed negative results for hepatitis B virus in the graft biopsy at month one after surgery. ConclusionsFrom the summary results of these cases, small-for-size left lobe liver APOLT can be used to treat decompensated cirrhosis. The application and popularization of this treatment regimen is expected to expand the donor pool and benefit more decompensated cirrhosis patients with lower Model for End-stage Liver Disease score.