B7-H4 is member of the B7 family that negatively regulates the immune response, which are important for fine-tuning of the tumor microenvironment. Dysregulation of B7-H4 expression has been associated with tumor progression. However, expression level of B7-H4 in hepatocellular carcinoma (HCC) tissues is still a controversial topic. In addition, whether serum B7-H4 expression of HCC patients has any clinical value is unknown. We compared serum levels of B7-H4 in patients with HCC and healthy controls by using the ELISA method. Association between serum B7-H4 expression level and clinical parameters of HCC was further investigated. Log-rank test and Kaplan-Meier method were employed to evaluate the overall survival rate of HCC patients. Univariate and multivariate analysis of prognostic factors were performed with the Cox regression model. Our results showed that HCC patients had significantly higher serum B7-H4 level as compared with healthy controls (P < 0.001). In addition, serum B7-H4 expression was correlated with HCC clinical parameters including serum AFP expression and TNM stage. HCC patients in the higher serum B7-H4 expression group had a poorer 5-year overall survival rate (P = 0.028). Moreover, serum B7-H4 expression was shown to be an independent prognostic factor for HCC (P = 0.034). The findings from this study suggest that serum B7-H4 is an independent prognostic indicator for HCC and may be a promising biomarker for early diagnosis as well as disease prognosis of HCC.