The invention relates to a thermal power plant power generator unit with a variable-frequency power generator unit and a steam turbine power generator unit in coaxial arrangement. The thermal power plant power generator unit comprises the steam turbine power generator unit consisting of a steam turbine and a first power generator, wherein the steam turbine drags the first power generator to rotate at a fixed speed to generate electricity, the thermal power plant power generator unit also comprises the variable-frequency power generator unit consisting of a speed regulation gearbox and a second power generator, the rotating speed of the steam turbine is output to the second power generator after the speed regulation by the speed regulation gearbox, and the electricity is supplied to a variable-frequency plant electricity consumption system through the second power generator. According to the thermal power plant power generator unit, industrial frequency electric energy can be generated by the first power generator to be used for on-line sales, and variable-frequency electric energy can also be generated by the second power generator to be used for self plant electricity consumption; compared with a conventional steam turbine power generator unit, the thermal power plant power generator unit has advantages that the output force of the steam turbine is sufficiently utilized, the operation efficiency of the steam turbine is improved, the electric energy is provided for major power loads in the plant through the second power generator, the integrated frequency conversion of the major power loads in the whole plant is realized, the plant electricity consumption rate is reduced, the electric energy is saved, the on-grid electric quantity is increased, and the power generating income of the power plant is improved.