Molting in insects is regulated by a variety of hormones that regulate different stages of growth and development. Bursicon binding to its receptor regulates a variety of processes, including the development and hardening of the cuticle, wing expansion and maturation, muscle contraction and migration of the edge of the egg cell, which are of great significance to the growth and development of insects. Bursicon consists of two subunits (BURS and PBURS) and is mainly synthesized in the thoracic and abdominal ganglions, which have independent biological activity in certain situations. The structure and evolution of the two subunits are conserved and their amino acid sequences have 11 cysteine residues. The bursicon receptor is a member of the G protein coupled receptor (GPCR) subfamily, which is rich in repeat leucine sequences and is named dLGR2. The C-terminal (containing multiple serine residues) and N-terminal regions (leucine-rich repetitive structure domain) of LGR2 play an important role in the exercise of normal functions. Bursicon is released into the haemolymph where it combines with LGR2 to activate the cAMP/PKA signal and phosphorylates tyrosine hydroxylase (TH). The activated TH transforms tyrosine into dopamine (DOPA), resulting in insect cuticle sclerotization and maturation. In addition, bursicon subunits can form a homologous dimer that activates the transcription factor Relish to regulate the immune response. This paper summarizes recent research on the molecular structure of bursicon and its receptor, its temporal and spatial expression, and its role in wing expansion and hardening, cuticle sclerotization and maturation, and the immune response. This review will provide a reference for further study of the role of bursicon in insects.