Objective:To analyze the genetic evolution characteristics of hemagglutinin (HA) and neuraminidase (NA) of influenza B virus in Tongling during 2019-2022 surveillance years.Methods:Twenty-two strains of Victoria influenza B virus isolated from our laboratory during 2019-2022 were selected for whole genome sequencing. The sequence comparison and phylogenetic analysis were conducted by using bioinformatic analysis software.Results:During 2019-2022, seasonal influenza in Tongling City was predominantly caused by influenza B Victoria lineage viruses, which fell within the V1A.3 branch. Among these, 14 strains isolated in the 2021-2022 season were further classified into the V1A.3a.2 sub-branch. Compared with vaccine strains, multiple amino acid mutation sites were detected in both HA and NA proteins of the 22 influenza B Victoria lineage viruses. Notably, all four major antigenic sites (120-loop, 150-loop, 160-helix, and 190-helix regions) in the HA protein exhibited variations. Although no mutations were detected at resistance sites on the NA protein, a change occurred in the glycosylation site at position 197 NETQ in the HA protein.Conclusions:The main amino acid sites of the HA protein of the influenza B Victoria lineage viruses in Tongling City from 2019 to 2022 have undergone significant variation, which may lead to antigenic drift. Therefore, it is essential to strengthen the monitoring of influenza virus mutations.