The invention provides a comprehensive utilization system for waste heat of an internal combustion engine. The comprehensive utilization system comprises a tail gas energy recovery system, an organic Rankine circulating system and a cooling water circulating system, the tail gas energy recovery system comprises a turbocharger, an intercooler, a waste gas pipeline and a gas-water heat exchanger, the organic Rankine circulating system comprises an organic working medium pump, an evaporator, an expander, a condenser and a power generator, and a cooling water circulating loop comprises a water incoming pipe, a water outgoing pipe, a three-way valve with an inlet, a first outlet and a second outlet, a water tank and a double heat exchange pipeline. Cooling water discharged from a water outlet of the internal combustion engine flows through the water outgoing pipe, the inlet of the three-way valve, the second outlet of the three-way valve, the double heat exchange pipeline, the gas-water heat exchanger, the evaporator, the water tank, the water incoming pipe to enter a water inlet of the internal combustion engine so as to realize cooling water heat exchange circulating. Temperature of the cooling water is increased under heating action of waste-gas waste heat discharged by the internal combustion engine, so that heat exchange efficiency of an organic working medium and the cooling water is improved, more heat can be recovered by the organic working medium, and waste heat utilization efficiency of the internal combustion engine is improved.