The invention discloses a diesel engine fuel oil electricity, gas and water combined heating system which mainly comprises an electric heating unit, a tail gas waste heat recovery unit, an anti-freezing solution circulation heating unit and a control circuit. The electric heating unit is composed of a fuel oil heating assisting device and an electric heater. The fuel oil heating assisting device is installed in front of an oil transferring pump. Little fuel oil in the heating assisting device and part of oil circuits of the electric heating unit is used for engine starting under low temperature, after engine starting, an anti-freezing solution and tail gas waste heat are used for heating an oil tank and other oil circuits until the temperature of the fuel oil in the whole oil circuits is higher than a fuel oil cold filtering point, and continuous supply of fuel oil is achieved. The diesel engine fuel oil electricity, gas and water combined heating system has the advantages that the preheating time of an engine before low-temperature starting is greatly shortened, the loads of a storage battery are greatly reduced, diesel oil with high condensation points can also be used by the diesel engine under the low temperature, oil consumption cost is saved, the structure is simple, installation is convenient, the structure of an original fuel oil system is not changed, and the diesel engine fuel oil electricity, gas and water combined heating system can be widely popularized.