A power management method of a computer system is provided. The method includes the following steps. Health states of a plurality of power supplies are detected to generate a detection signal. Output powers provided by the power supplies are received to calculate a total maximum output power of the power supplies. An interrupt is generated by triggering a configuration management program according to the total maximum output power or the detection signal. The interrupt is processed by an interrupt handler to adjust a power consumption of a central processing unit (CPU).