A turbocharger with a two-stage supercharging function relates to the technical field of turbocharger equipment of internal combustion engines of passenger motor vehicles and comprises a high-pressure turbocharger and a low-pressure turbocharger. An air channel which is communicated with a high-pressure turbine air inlet and a low-pressure turbine air inlet is arranged on a body of a high-pressure turbine shell, a flow control valve which is used for controlling airflow in the air channel is mounted on the air channel, a low-pressure turbine shell is integrally connected with the high-pressure turbine shell, and the low-pressure turbine air inlet is connected with a high-pressure turbine exhaust opening. The turbocharger with the two-stage supercharging function not only solves the conflict between high torque of a passenger motor vehicle an engine at a low rotation speed and maximization of power at a high rotation speed, but also is compact in structure, small in occupied space, fine in sealing performance, high in operational reliability and simple and convenient in production and installation, and has a high service value when used on passenger motor vehicles and the like with narrow engine spaces.