The invention discloses a double-buoyancy hybrid driving large-scale heavy-duty underwater vehicle. The double-buoyancy hybrid driving large-scale heavy-duty underwater vehicle comprises a bow assembly, a middle assembly and a tail assembly, wherein the bow assembly comprises a cable throwing module, a bow shell, a bow connecting ring and a front glass fiber reinforced plastic shell which are sequentially connected from front to back, the cable throwing module and the front end of the bow shell are fixedly connected through annular bolts, the bow shell and the front glass fiber reinforced plastic shell are connected through the bow connection ring, the interior of the front glass fiber reinforced plastic shell is connected with a front buoyancy adjusting modular through front connecting fixing blocks, the middle assembly comprises a middle cabin front connecting ring, a middle cabin shell and a middle cabin rear connecting ring which are sequentially arranged from front to back, a power supply module, an attitude adjusting module and a control module are arranged in the middle cabin shell, and the tail assembly comprises a rear glass fiber reinforced plastic shell, rear connectingfixing blocks, wings, a rear buoyancy adjusting module, wing fixing strips, a communication module, a load rejection part, a cross rudder and a propeller. The vehicle has the advantages of small resistance and low power consumption, and is suitable for carrying various sensors to carry out underwater biochemical parameter observation.