The first generation of long-acting interferon pellets can use 12kD linear polyethylene glycol molecule, which has poor stability and short effective concentration maintenance time. The second generation of long-acting interferon pellets used 40kD U-shaped polyethylene glycol molecules, and the stability and blood concentration were improved, but the neutralizing antibody production rate was high when interferon α-2a subtype was used. The third generation of long-acting interferon adopts the innovative 40kD, Y-type polyethylene glycol molecular structure and the lysine modified structure of interferon α-2b 134, which combines the advantages of the first generation and the second generation of long-acting interferon and makes independent innovation. This is also the first self-developed long-acting interferon in China, with the same curative effect as imported products, more stable structure and lower production rate of neutralizing antibodies.