The invention discloses a flue gas purifying chimney utilizing waste heat to generate power. The chimney comprises a chimney barrel body, wherein a smoke inlet is formed at the bottom of the chimney barrel body, and a smoke discharge opening is formed in the top of the chimney barrel body; a rain resisting cover is arranged on the smoke discharge opening of the chimney barrel body; and a heat sinking device, a heat energy generator, a cleaning layer, an air exhaust fan and a fan motor are arranged in the chimney barrel body, wherein the heat sinking device recovers the waste heat of the flue gas from the smoke inlet, the heat sunk by the heat sinking device is transformed to the electric energy by the heat energy generator, the cleaning layer is located above the heat sinking device and filters the flue gas, the air exhaust fan is located above the cleaning layer, and the fan motor drives the air exhaust fan and is electrically connected with the heat energy generator. The Flue gas purifying chimney utilizing waste heat to generate power is reasonable in structure and design, and meanwhile, the functions of resisting rain, generating power, lighting and filtering are achieved; the heat in the flue gas is transformed to the electric energy by the heat sinking device and the heat energy generator, and the electric energy is supplied for an air discharge machine of the chimney, energy is saved, the chimney is environmentally friendly, and waste of energy is avoided; and the electric energy consumed when the chimney works are all came from the energy transformation of the chimney, energy transformation is not affected by the effect of the weather and the environment, and the working stability is good.