The invention relates to a distributed energy system for solving corrosion and scaling of an open type cooling system of a combustion engine and a working method. The distributed energy system comprises an air inlet pipeline, an air inlet heat exchanger, a fuel gas inlet pipeline, an internal combustion engine, an internal combustion engine generator, a gas turbine, an atomizing air cooler, an LCIcooler, a turbine lubricating oil cooler, a waste heat boiler, a steam turbine, a steam turbine generator, a smoke type lithium bromide unit, a cooling water pump, a steam type lithium bromide unit,a circulating water pump, a water supplementing tank, a medical dosing water feeding pump, a medical dosing device, a compensation heat exchanger and an electric refrigeration device. According to thesystem and the method, on one hand, the air inlet temperature of the combustion engine can be effectively reduced, the heat of a cooling water is fully utilized, the operation efficiency of the combustion engine is improved, on the other hand, the corrosion of a cooling water system can be prevented, accumulating allowance of a heat exchange area needing to be considered during design of the heatexchangers is reduced, the gradient utilization of energy is realized, the energy of the exhaust gas and the energy of the steam can be effectively utilized, and the utilization efficiency of the energy is greatly improved.