The invention which is supplied through the pre-heater, provide energy for preheating the feed that received received energy of ten won medium energy supply unit, of the reference to the working fluid to ten won medium supplied through the energy service level temperature range that provides the externally from the outside the first turbine through the pre-heater to ten won media being supplied to the evaporator, the gas supplied through the evaporator that receives supplies the working fluid preheated to a temperature in the range of the reference level vaporized into a gas for driving converts into mechanical energy, driving the first turbine a first power generation block for generating power by being connected to the first power generation block is connected to the first power converter, a first power converter for converting the electric power produced through the first power generation block by the power of a certain level, the first If the gas to be supplied to receive the first power supply cows, fed to the first turbine to the converted power to a constant level through the power converter exceeds the reference range, which may allow the first turbine, when supplied gas from the evaporator, mechanical energy was converted to the driven while the first turbine and side by side is connected with the second turbine, the second power generation block for generating power by driving the second turbine, second power generation block that is arranged in parallel to the production via the second power generation block a second power converter, a second power converter being connected to the second power second power converter through the fed the converted power to a constant level supply cows, the first turbine or the second turbine, which converts the power into electric power of a constant level the cooled working condensation supplied to the condenser, the refrigerant in the condenser for condensing the gas in a liquid state, and fed through the engine cooler, a condenser for recovering the refrigerant from the condenser condensed continuously cooling the overheated working fluid by the condenser is supplied via be connected between the storage tank and the storage tank and the pre-heater to store the fluid provides an organic Rankine cycle power generation system including a pump for pumping to supply the condensed cooling the working fluid stored in the storage tank to the pre-heater.