The invention discloses a CO2 compressive liquidation adjustable compound system based on recovery of internal energy of a power plant, and belongs to the technical field of energy and environments. The system comprises a three-way valve, liquid separating tanks, diverters, an expander, heat exchangers, compressor interstage heat exchangers, multiple stages of CO2 compressors, compressors, a condenser, mixers, a cold side evaporator, throttle valves, a generator set and CO2 booster pumps. The system comprises an adjustable CO2 compressive liquidation unit and an internal energy integrated system. Waste heat in multiple varieties and at multiple temperature levels is integrally used section by section at multiple stages, the CO2 flow is dynamically adjusted, a good effect is achieved for extracting at different temperature levels and coping with the generating capacity fluctuation, the system is highly integrated, nonreversible losses generated in the heat exchange process are reduced,the energy consumption of the system is obviously reduced, the energy utilization rate is remarkably increased, and the system can be widely applied to the field of carbon trapping and compressing.