The utility model discloses a thermal power plant exhaust vapor pressurization recycling device which is simple in structure, pressurizes exhaust vapor and recycles heat energy of residual vapor. Exhaust vapor conveyed by a pipeline of a thermal power plant is concentrated in a gas storage tank through a gas inlet, condensate water in the gas storage tank is discharged, then residual vapor is pressurized into another large container constant-pressure tank with the volume of 3 m<3> through a vapor separator by means of a graphite piston type oil-free lubricating ring vapor compressor, an electrical-connection point pressure gauge at the upper portion of the constant-pressure tank automatically controls the vapor compressor to start or stop, and low-pressure vapor with the density lower than 4 kg/cm<3> and the temperature lower than 159 DEG C is pressurized into vapor with the density of 10 kg/cm<3> to 134 kg/cm<3> and the temperature higher than 180 DEG C to be recycled.