The basic helix–loop–helix (bHLH) gene family is a crucial regulator in plants, orchestrating various developmental processes, particularly flower formation, and mediating responses to hormonal signals. The molecular mechanism of bamboo flowering regulation remains unresolved, limiting bamboo breeding efforts. In this study, we identified 309 bHLH genes and divided them into 23 subfamilies. Structural analysis revealed that proteins in specific DlbHLH subfamilies are highly conserved. Collinearity analysis indicates that the amplification of the DlbHLH gene family primarily occurs through segmental duplications. The structural diversity of these duplicated genes may account for their functional variability. Many DlbHLHs are expressed during flower development, indicating the bHLH gene’s significant role in this process. In the promoter region of DlbHLHs, different homeopathic elements involved in light response and hormone response co-exist, indicating that DlbHLHs are related to the regulation of the flower development of D. latiflorus.