Energy-saving efficient system for heating process water

An energy-saving efficient system for heating process water. A process water pipe is successively connected with a heating device, a low temperature process water treatment device and a high temperature process water treatment device of an original system. The system is characterized in that a low temperature waste heat heating device and a medium temperature waste heat heating device are orderly arranged between the process water pipe and the heating device of the original system, the low temperature waste heat heating device is respectively communicated with a low temperature waste heat heat flow pipe and a low temperature waste heat cold flow pipe, and the medium temperature waste heat heating device is respectively communicated with a medium temperature waste heat heat flow pipe and a medium temperature waste cold flow pipe. The energy-saving efficient system for heating process water provided by the invention makes full usage of the large amount of waste heat abandoned in the environment or used by low efficiency factory around factories as a heat source to heat the process water, realizes energy utilization with fitting temperature and efficient echelon, and meets the principles of energy conservation and environmental protection.