The invention disclose a novel polyether polyamine compound with a structural formula (I) and a synthesis method thereof as well as a maintenance product for a diesel motor fuel system. The polyether polyamine compound has the characteristics of efficiently clearing deposited carbon of the diesel (gasoline) motor fuel system and thoroughly clearing the deposited carbon of an air intake system anda combustion chamber of a diesel motor. By using the maintenance product for the diesel motor fuel system, the economic efficiency of fuel can be improved, the demounting-free maintenance of the diesel motor can be achieved, the tail gas emission of an automobile is reduced, and energy conservation and environmental protection can be realized.