In recent years, thermoplastic composites have been gradually used in aerospace, marine equipment, transportation, and other fields because of their excellent mechanical properties, environmental resistance, and recyclable potential. They can be prepared by various forming processes. Among them, overmolding, which is a unique molding process for thermoplastic composites can combine the prefabricated parts with the injection molding process. Due to the diversity of its structure and material design, process flexibility, it has gradually attracted wide attention from researchers. Based on the whole process of overmolding, this paper will introduce its research progress, including material system, manufacturing and pre-treatment of prefabricated parts, injection molding, post-treatment of structures, as well as the numerical simulation means and combined application methods involved in this process, and analyze the current process difficulties and future development direction.