A power management method, used for power management of an electronic device, wherein the electronic device comprises a central processing unit, CPU, and a storage, the storage stores a plurality of program instructions respectively corresponding to boot firmware, an operating system, OS, and intelligent management unit, IMU, firmware, the plurality of program instructions are read and executed by the CPU to implement functions of the boot firmware, the OS, and the IMU firmware, and the power management method is performed by the IMU firmware and comprises: obtaining an intelligent management unit power management, IMU PM, execution notification before the OS runs, wherein the IMU PM execution notification is sent by the boot firmware after the boot firmware determines, before the OS runs, that power management, PM, is to be performed by the IMU firmware, and the boot firmware is further configured to prevent, before the OS runs, the OS from performing operating system power management, OS PM, wherein the boot firmware is configured to prevent, by using one of the following methods before the OS runs, the OS from performing operating system power management, OS PM: creating a first advanced configuration and power interface, ACPI, table, and reporting the first ACPI table to the OS, wherein the first ACPI table does not comprise a performance status table, to prevent the OS from performing OS PM, and the performance status table is a performance support status, PSS, table or a continuous performance control, CPC, table; or creating a second ACPI table, and reporting the second ACPI table to the OS, wherein the second ACPI table comprises a performance status table, and frequency adjustable values in the performance status table comprised in the second ACPI table are set to a same preset value, or a header of the performance status table comprised in the second ACPI table is a value with an undefined range, to prevent the OS from performing OS PM; after determining, based on the IMU PM execution notification, that PM is to be performed on the CPU by the IMU firmware, obtaining a current performance parameter of the CPU, wherein the performance parameter comprises one or more of power consumption, a temperature, or usage of the CPU; and performing power management on the CPU based on the performance parameter. obtaining an intelligent management unit power management, IMU PM, execution notification before the OS runs, wherein the IMU PM execution notification is sent by the boot firmware after the boot firmware determines, before the OS runs, that power management, PM, is to be performed by the IMU firmware, and the boot firmware is further configured to prevent, before the OS runs, the OS from performing operating system power management, OS PM, wherein the boot firmware is configured to prevent, by using one of the following methods before the OS runs, the OS from performing operating system power management, OS PM: creating a first advanced configuration and power interface, ACPI, table, and reporting the first ACPI table to the OS, wherein the first ACPI table does not comprise a performance status table, to prevent the OS from performing OS PM, and the performance status table is a performance support status, PSS, table or a continuous performance control, CPC, table; or creating a second ACPI table, and reporting the second ACPI table to the OS, wherein the second ACPI table comprises a performance status table, and frequency adjustable values in the performance status table comprised in the second ACPI table are set to a same preset value, or a header of the performance status table comprised in the second ACPI table is a value with an undefined range, to prevent the OS from performing OS PM; creating a first advanced configuration and power interface, ACPI, table, and reporting the first ACPI table to the OS, wherein the first ACPI table does not comprise a performance status table, to prevent the OS from performing OS PM, and the performance status table is a performance support status, PSS, table or a continuous performance control, CPC, table; or creating a second ACPI table, and reporting the second ACPI table to the OS, wherein the second ACPI table comprises a performance status table, and frequency adjustable values in the performance status table comprised in the second ACPI table are set to a same preset value, or a header of the performance status table comprised in the second ACPI table is a value with an undefined range, to prevent the OS from performing OS PM; after determining, based on the IMU PM execution notification, that PM is to be performed on the CPU by the IMU firmware, obtaining a current performance parameter of the CPU, wherein the performance parameter comprises one or more of power consumption, a temperature, or usage of the CPU; and performing power management on the CPU based on the performance parameter.