The invention discloses a thermal energy cascade utilization type thermoelectric power generation device, which comprises a combustion chamber, a combustor and a flue, and is characterized in that the outer wall of the combustion chamber is provided with a high-temperature thermoelectric power generation module, the outer wall of the flue is provided with an intermediate-temperature thermoelectric power generation module, the outer side of the high-temperature thermoelectric power generation module is provided with a cooling water sleeve, an outlet of the cooling water sleeve is communicated with a cooling water re-heater, and an outlet of the cooling water re-heater is communicated with a hot end of low-temperature thermoelectric power generation module through a cooling water pipe. Compared with the prior art, the thermal energy cascade utilization type thermoelectric power generation device has the advantages that three different modules, namely, the high-temperature thermoelectric power generation module, the intermediate-temperature thermoelectric power generation module and the low-temperature thermoelectric power generation module, are arranged in a high-temperature region, an intermediate-temperature region and a low-temperature region of the same system respectively, thereby forming cascade utilization for a heat source, and thus enabling the energy utilization rate and the efficiency of the whole thermoelectric power generation system to be greatly improved.