NOVELTY - A technical method for efficiently recycling waste heat and preparing clean fuel by using dimethyl ether comprises reacting dimethyl ether and water under middle-low temperature heat to generate hydrogen and carbon dioxide at about 300 degrees C; or reacting dimethyl ether and carbon dioxide under middle-low temperature heat to generate hydrogen and carbon monoxide at about 300 degrees C.    USE - The method is useful for efficiently recycling waste heat and preparing clean fuel by using dimethyl ether (claimed). The hydrogen energy is useful as a clean energy and fuel of a fuel battery or other energy supplying devices, to provide electric power, air conditioner, and heat for the industry or for the people.    ADVANTAGE - The method efficiently uses and recycles the waste heat, to prepare the clean energy-hydrogen energy, synchronously, consumes the greenhouse gases carbon dioxide; it releases the energy supply tension, improves the environment, and improves the producing efficacy of the company.    DETAILED DESCRIPTION - A technical method for efficiently recycling waste heat and preparing clean fuel by using dimethyl ether comprises reacting dimethyl ether and water under middle-low temperature heat to generate hydrogen and carbon dioxide at about 300 degrees C, where the hydrogen energy obtained after the reaction is higher about 10% than the combustion heat of the dimethyl ether; or reacting dimethyl ether and carbon dioxide under middle-low temperature heat to generate hydrogen and carbon monoxide at about 300 degrees C, where the hydrogen and the carbon monoxide obtained after the reaction is higher about 18% than the combustion heat of the dimethyl ether. An INDEPENDENT CLAIM is included for a technical device for efficiently recycling waste heat and preparing clean fuel by using dimethyl ether comprising evaporator, reactor, filter valve, and pipeline connecting the evaporator, the reactor, and the filter valve; where the entrance and the exit of the reactor are respectively connected with the exit of the evaporator and the entrance of the filter valve, to form the loop of the device.    DESCRIPTION OF DRAWING(S) - The drawing shows the block diagram of the device for efficiently recycling waste heat and preparing clean fuel by using dimethyl ether (Drawing includes non-English language text).