β-cyclodextrin (β-CD) is a kind of natural polymer material with wide application. It has the advantages of wide sources, low cost, renewable and biodegradable. In recent years, β-CD has been applied in the field of flame retardant because of its special structure and excellent char formation performance. This article briefly describes the relevant characteristics, sources, structure and properties of β-CD, and discusses the application of β-CD as a char-forming agent, synergist, and an integrated intumescent flame retardant. It describes the flame retardant mechanism and some defects of β-CD as a flame retardant. It is believed that in-depth research of β-CD, improving the flame retardant efficiency, matching it with other ingredients reasonably, enhancing the synergistic effect, and developing new composite and efficient β-CD flame retardants are the future development direction.