The utility model discloses an engine waste heat recovery system based on an organic Rankine cycle. The engine waste heat recovery system comprises an engine tail gas loop, an engine cylinder sleeve loop, a refrigerant loop and an external cooling water loop. The engine waste heat recovery system recycles engine waste heat fully, and is high in recovered energy, higher in recovery efficiency, and smooth and steady in whole system operation, and more compact in structural arrangement. The engine waste heat recovery system is mainly characterized by comprising an integrated heat source recovery system of engine tail gas and cylinder sleeve water, and a refrigerant ORC system mainly composed of an evaporator, a condenser, an expansion machine and a refrigerant pump. Engine waste heat recycling and reusing can be achieved by effectively controlling various parts of the engine waste heat recovery system, generating capacity consumed by unit fuel of an engine is further improved, and investment return cycle of the engine is shortened.