The objective of this study was to evaluate the efficacy and safety of TVAX-008 Injection in a multicenter, randomized, double-blind, placebo-controlled, parallel-group Phase II clinical trial in NAs-treated subjects with chronic hepatitis B. 80 subjects are planned to be enrolled in this study and divided into 2 groups. After a screening period of no more than 4 weeks, eligible subjects will be randomly assigned to enter the double-blind treatment period according to the ratio of 1:1, and receive TVAX-008 injection or placebo in combination with NAs for 24 weeks. At the end of the double-blind treatment period, subjects with HBsAg negative and HBsAg\>100 mIU/mL continued to be followed up to Week 73; subjects with HBsAg not negative or HBsAg negative but HBsAg ≤100 mIU/mL entered the open-label treatment period and received TVAX-008 injection combined with NAs for 24 weeks, and continued to be followed up for 24 weeks after the end of the open-label treatment period.