The invention provides a multistage compression cycle power generation method by adopting supercritical carbon dioxide, and belongs to the technical field of waste heat power generation. The method comprises the steps that a steam turbine is driven by using high-temperature S-CO2 working media for power generation; the S-CO2 working media cooled after power generation enter cycling units, and aredivided in the cycling units; the divided S-CO2 working media in a branch A are subjected to heat exchange and compression, and the S-CO2 working media in a branch B are subjected to multistage cooling and compression; and the S-CO2 working media in the branch A and the branch B are mixed and cycled to enter power generation units. According to the method, the problems that the outlet working medium pressure of the steam turbine and the inlet working medium pressure of a compressor are interdependent and the parameters can not be adjusted separately in supercritical carbon dioxide Brayton cycles are solved, so that the cycle efficiency of the system is improved greatly.