Hepatic venous pressure gradient (HVPG) is the gold standard for portal pressure in cirrhosis, but most previous studies focused on the diagnostic value of clinically significant portal hypertension (CSPH) based on the correlation between liver stiffness (LS) and HVPG in hepatitis C virus (HCV) patients and alcoholic liver. Therefore, it is necessary to clarify the diagnostic value of LS for CSPH and the correlation with HVPG in hepatitis B virus (HBV) patients. A total of 137 patients from the Fifth Medical Center of PLA General Hospital were divided into HBV group and non-HBV group according to etiology. Correlation analysis and ROC were used to analyze the correlation between LS and HVPG and the diagnostic value of CSPH. There was a good correlation between LS and HVPG in the total cohort and non-HBV cohort (r = 0.398, P < 0.001; r = 0.575, P < 0.001, respectively). However, the correlation between LS and HVPG was acceptable in the HBV cohort (r = 0.316, P = 0.002). When adjustment for age, MELD score, and INR, the result was still the same. Similar results were observed in the prediction for CSPH. LS showed good diagnostic value for CSPH in the total cohort and non-HBV cohort (AUC = 0.732, AUC = 0.829, respectively). However, it performed poorly in the HBV cohort (AUC = 0.689). The etiology of HBV might affect the diagnostic performance of LS for predicting CSPH.