The invention provides an energy consumption management method for an embedded system, implemented by dynamic power supply management support module, comprising: policy management module, idle detection module, and performance detection module, where the policy management module makes effective power supply management at system layer so as to implement system performance and power saving, and gives attention to idle state and executed load of system, and self-adaptively regulates equipment idle time according to system task executing state and makes the system enter a corresponding low-power state when the idle time continues to a certain extent; the idle detection module provides idle information of CPU and operating system and monitors the idle thread or activity of a given working load in the operating system and provides policy-making parameter information for the policy management module; and the performance detection module monitors CPU utilization ratio and utilization conditions of main memory and provides accurate executed load information for the policy management module.