The successful application of ex vivo liver resection and autotransplantation (ERAT) has gained widespread attention for the treatment of end-stage hepatic alveolar echinococcosis, which is considered to be unresectable by conventional methods due to extensive invasion of the extra- and intrahepatic vasculature. However, data on remnant liver volume (RLV) are limited, and the safe volume limit of remnant liver is still unclear. To determine the effect of liver volume in the technically developed era, we investigated the impact of the remnant liver-to-standard liver volume ratio (RLV/SLV) on the outcomes of ERAT. From February 2014 to May 2018, 56 ERAT procedures were performed. Eleven patients with an RLV/SLV < 40% (group S) were compared with 45 patients with an RLV/SLV ≥ 40% (group L). Serial changes in postoperative serum total bilirubin, alanine aminotransferase, aspartate aminotransferase, and international normalized ratio were comparable in both groups. The incidences of postoperative complications did not significantly differ between the two groups. Three patients died of intra-abdominal bleeding, acute cerebral hemorrhage, and severe liver dysfunction. In RLV estimation analysis, the actual RLV and RLV/SLV were significantly smaller than the expected RLV and RLV/SLV as determined by preoperative three-dimensional reconstruction software in patients with hepatic venous outflow obstruction. Patients with a smaller RLV/SLV did not have outcomes inferior to those with a larger RLV/SLV. Further studies are warranted to clarify the factors that contribute to preoperative volumetric estimation and the safe lower limits for ERAT.