A thermal management system for a hybrid vehicle includes an expander, a heat exchanger, a condenser, a water tank, a pump, a heat exchanger for a battery pack, a heat exchanger for a motor, a water cooling jacket for an engine, an exhaust gas heat exchanger for an engine, a valve, and so on. According to the present disclosure, in thermal management loops, different operating modes of the system can be switched by controlling the open-close and opening of the valve. In this way, a series/parallel connection of thermal management branches of an electrical system and an engine system is fulfilled to meet the requirements for heat dissipation and preheating, and flux in each branch is regulated to fulfill thermal management according to different driving conditions of a hybrid vehicle.