Objective: To determine the risk factors for posthepatectomy liver failure in patients with Child-Pugh A liver function. Methods: From October 2010 to April 2014, 427 consecutive patients with primary liver cancer and preoperative Child-Pugh classification score A liver function undergoing hepatectomy were enrolled. All operations were performed by the same surgical team and under hepatic inflow occlusion with a clamp/unclamp time of 15 min/5 min. The clinical data of the patients were collected, and the risk factors for posthepatectomy liver failure were analyzed. Results: Among the 427 patients, 362 cases were male and 65 were female, with an average age of (51.1±10.4) years; 391 cases underwent surgery for hepatocellular carcinoma (HCC), 31 cases for intrahepatic cholangiocarcinoma (ICC) and 5 cases for mixed HCC and ICC. Of the cases, 86.4% (369/427) had a background of hepatitis B virus infection and 54.8% (234/427) had concomitant cirrhosis; 358 cases (83.8%) had resections of ≤3 segments and 69 cases (16.2%) had resections of ≥4 segments. Seventeen patients (4.0%) developed liver failure after hepatectomy, of whom 10 cases manifested as hyperbilirubinemia unrelated to biliary obstruction or bile leak, 6 cases had clinically apparent ascites and prolonged prothrombin time, and one case had hepatic encephalopathy and died on postoperative day 21. Univariate analysis showed that age ≥ 60 and prealbumin <170 g/L were significantly related to posthepatectomy liver failure (P=0.045, P=0.009), and multivariate analysis identified that prealbumin <170 g/L was independent risk factor for posthepatectomy liver failure (HR=3.192; 95% CI=1.185–8.601, P=0.022). Conclusion: Serum prealbumin level is an independent influential factor for posthepatectomy liver failure in patients with Child-Pugh score A liver function. So improving the nutritional status of the patients may reduce the incidence of posthepatectomy liver failure.