Abstract B cells play immunomodulatory roles mainly by presenting antigens and producing antibodies. In recent years, some B cells were shown to exhibit regulatory functions. This type of B cell was named regulatory B cells (Bregs). Bregs can mediate immune tolerance to inhibit excessive inflammatory responses and to accelerate recovery of inflammation by producing interleukin 10 and/or transforming growth factor β1 and other inhibitory cytokines. Studies showed that Bregs play important roles in parasites, bacteria, and viral infections. This study reviews biological characteristics, functions, and microsignal regulation of Bregs and their mechanism in infectious diseases and related research progress.