Our previous studies unexpectedly indicated that the level of serum hepatitis B core antibody (anti-HBc) was positively correlated with the serum alanine aminotransferase (ALT) level. The aim of this study was to determine whether anti-HBc could serve as a potential biomarker for the detection of liver inflammation in chronic hepatitis B (CHB) patients, especially in patients with normal ALT levels. Serum anti-HBc levels were quantified in 655 treatment-naïve CHB patients, including 45 patients who underwent two liver biopsies (baseline phase and the 78th weeks of antiviral-treatment). Serum anti-HBc levels increased significantly along with the increasing histology activity index (HAI) score. After antiviral-treatment, patients with HAI score reduction had significant decline in serum anti-HBc level. Multivariate analysis showed that anti-HBc was independently associated with moderate-to-severe hepatic inflammation in patients with normal ALT level. Furthermore, serum anti-HBc showed a high diagnostic accuracy for predicting moderate-to-severe inflammation in both hepatitis B e antigen (HBeAg)-positive and HBeAg-negative CHB patients with normal ALT levels (area under the curve, AUC = 0.87 and 0.75; respectively). Thus, anti-HBc may be a strong indicator for assessing the hepatic inflammatory degree and used for antiviral treatment decisions in CHB patients with normal ALT levels.