Accumulated studies have reported the prognostic significance of prealbumin in liver cancer, but the results were not conclusive. The aim of this study was to evaluate the association between pretreatment serum prealbumin and clinical outcome of liver cancer patients through a meta-analysis. We comprehensively searched EMBASE, PubMed, Web of Science and the Cochrane library to identify eligible studies. The pooled hazard ratios (HRs) and their 95% confidence intervals (CIs) were utilized to evaluate the prognostic value of pretreatment serum prealbumin in overall survival (OS) and recurrence-free survival (RFS) of liver cancer patients. A total of 3470 patients from 10 eligible studies were finally included for analysis. The combined effects of prealbumin on liver cancer patients' OS and RFS were HR = 1.83, 95% CI: 1.46-2.30, P < 0.001 and HR = 1.47, 95% CI: 1.01-2.14, P = 0.045, respectively. Sensitivity and subgroup analysis showed that the pooled HR of prealbumin on liver cancer patients' OS was stable. Since potential publication bias was identified in the OS studies, the trim-and-fill method therefore was performed to explore publication bias, and the results showed reliability. This meta-analysis shows that low pretreatment serum prealbumin is significantly associated with poor prognosis of liver cancer patients.