Hemocyanin, an important respiratory protein, is involved in multiple physiological processes including oxygen transport, immune defense and protein storage, and plays an important role in the development and environmental adaptation of insects. In recent years, hemocyanin has been found in ametabolous insects and its evolution and function has become a popular research topic for both domestic and overseas scholars. This paper reviews the structure and function of insect hemocyanin, focusing on the effects of hemocyanin on oxygen transport and hypoxic adaptation in insects.