This study included 117 HBeAg-negative chronic hepatitis B patients with incomplete response to initial treatment (HBV DNA ≥20 IU/mL after 1 year of treatment), comparing the efficacy and safety of combined therapy (original medicine + second nucleoside (acid) analog) with sequential therapy (discontinuing original medicine and replacing with new medicine). The results show that the viral clearance rate in the combined group was significantly higher than that in the sequential group at 24 and 48 weeks (95.92% vs 80.88%, P=0.016; 97.96% vs 86.76%, P=0.044), especially in the high viral load subgroup (≥10⁴ IU/mL), with a more obvious advantage; while there was no difference in efficacy between the two groups for patients with low viral load. There were no significant differences in the rate of ALT normalization and safety indicators such as renal function, myocardial enzymes, and blood lipids between the two groups.