Interferon is a broad-spectrum antiviral drug. In the mid-1970s, it was discovered that patients with slow hepatitis B had a low ability to produce interferon on their own and that the application of exogenous interferon could produce anti-hepatitis B virus efficacy, after which interferon was used for slow hepatitis B treatment. The world’s first genetically engineered interferon came from the United States, and this drug was approved by the U.S. Drug Enforcement Administration in 1991 for the treatment of slow hepatitis B. Over the next decade or so, it has made a significant contribution to the field of hepatitis B treatment. However, interferon has an obvious disadvantage, that is, the molecular weight is small, after the injection, most of the kidney “leakage” out of the body, 4 hours after injection, half of the excretion, 12 hours, the body of interferon basically completely out of the body. In order to maintain the efficacy of the treatment, it had to be injected several times in the past, which is not only inconvenient and increases the patient’s pain, but also the efficacy of the virus inhibition is not stable and long-lasting. To overcome this problem, scientists conducted a long-term study and discovered that a substance called polyethylene glycol can make the molecular weight of interferon larger and prevent it from leaking out of the kidneys easily. The polyethylene glycol is added to the interferon in the form of a branched chain and does not change the action of the interferon itself or cause any other harm to the body. Interferon with the addition of pegylated glycol branched chains is called pegylated interferon, and is also known as “long-acting” interferon because it is more stable in the body after injection and has a longer duration of action. Meanwhile, the previous interferons are called regular interferons. In brief, the difference between long-acting interferon and regular interferon stems from their molecular weights, the former being more stable and therefore longer acting, requiring only one dose a week. Long-acting interferons have been approved for the treatment of chronic hepatitis B since 2000, and a growing body of clinical research and experience has repeatedly confirmed that long-acting interferons are more effective against the hepatitis B virus than regular interferons. Currently, there are two types of long-acting interferons: pegylated interferon alpha-2a and pegylated interferon alpha-2b. Both drugs are based on the addition of pegylated interferon branched chains, with the former having a larger molecular weight of 40 KD and the latter 12 KD, and the former is generally considered to be more stable. Of course, both have a longer duration of action and better efficacy compared to regular interferon. The price of long-acting interferon is also increased compared to ordinary interferon, but the course of treatment of these drugs is more fixed, about a year, so the cost of treatment is also relatively fixed, patients understand the advantages and disadvantages, after full preparation to start and adhere to treatment, is the greatest guarantee of successful treatment.