I. Anti-viral mechanism of nucleoside (acid) analogues: Acting on the polymerase region of HBV, the nucleoside is substituted for a structurally similar nucleoside needed to extend the polymerase chain during viral replication, terminating chain extension and thus inhibiting viral replication. The treatment drug of choice: 1, lamivudine (lamivudine): the dose is 100mg daily. well tolerated. The proportion of patients with viral resistance mutation increases with the prolongation of drug use. 2. adefovir dipivoxil: the dose is 10 mg daily. there is some nephrotoxicity at higher doses. Serum creatinine and blood phosphorus should be monitored regularly. The incidence of drug resistance is low. 3, entecavir (entecavir): 0.5 mg daily orally; 1 mg daily for those with YMDD mutations. The incidence of resistance was 0 at 1 year of treatment in primary care patients. 4. telbivudine: 600 mg orally once daily, not affected by food. It has good safety and tolerability. It is a class B drug in the U.S. FDA drug safety classification for pregnancy. Antiviral treatment course: The course of treatment depends on the patient’s condition: 1. HBeAg-positive patients with chronic hepatitis B: continue the drug for more than 1 year after HBeAg seroconversion; 2. HBeAg-negative patients with chronic hepatitis B: at least 2 years; 3. Patients with cirrhosis: long-term application is required. 4.Nucleoside (acid) antiviral therapy should not be given in reduced doses either during or at the end of treatment.