The invention discloses a medium and high temperature flue gas waste heat dual-working-medium combined cycle power generation device. The medium and high temperature flue gas waste heat dual-working-medium combined cycle power generation device comprises a water and water vapor cycle part and a low boiling point organic working medium Rankine cycle part, and the water and water vapor cycle part and the low boiling point organic working medium Rankine cycle part form a dual-working-medium combined cycle system for efficiently recycling medium and high temperature flue gas which is higher than 300 DEG C. According to the dual-working-medium combined cycle power generation device, the water and water vapor cycle part and the low boiling point organic working medium Rankine cycle part form the dual-working-medium combined cycle system for efficiently recycling the medium and high temperature flue gas, organic working media are heated by pumping water from a waste heat boiler drum, cooled high-pressure water is fed back to an inlet of an economizer of a waste heat boiler, the economizer is free from limitation of an evaporator, the heat absorption capacity is set according to the exhaust gas temperature of the waste heat boiler, and therefore the cycle device can achieve the optimal waste heat utilization rate under any working condition.