The invention relates to a semiconductor power generation device using flue gas waste heat of a rear smoke channel of a boiler. The semiconductor power generation device comprises a boiler rear smoke channel (101) and a thermoelectric power generation device (109). The thermoelectric power generation device consists of a hot end surface (110), a cold end surface (102), a leading-out wire (103), welding points (104), guide plates (106), P type semiconductors (107), N type semiconductors (108), and a thermal insulation material layer (111). Cooling holes (105) are formed in the cold end surface. The thermoelectric power generation device is connected with the boiler rear smoke channel by the thermal insulation material layer. According to the thermoelectric power generation device, a temperature difference is generated between the hot end surface (110) formed by flue gas waste heat and the cold end surface (102) under an atmospheric temperature, so that the P type semiconductors and the N type semiconductors generate electromotive forces respectively. The P type semiconductors and the N type semiconductors are connected in series by the guide plates; and the generated electrical energy is outputted to the user based on the welding points and the leading-out wire. According to the invention, with the heat sensitivity of the semiconductors, the flue gas waste heat is utilized and the low-temperature waste heat is converted into the electric energy directly, so that no pollution is caused and installation is convenient; and the effect of energy conservation and emission reduction is realized well.