Abstract: A method for obtaining a power state of an advanced configuration and power interface (ACPI) of a computer starting a baseboard management controller (BMC) after a power supply system of the computer is powered on. The BMC detects if a power signal from the power supply system is high level or low level. If the power signal is high level, the BMC determines that the power state of the ACPI is in a power state S0. If the power signal is low level, the BMC determines that the system power state of the ACPI is in a power state S5. A basic input output system (BIOS) detects if the system power state has changed. If the system power state has changed, the BIOS sends a current power state to the BMC. The BMC sends the power state to a system management software (SMS) of the operating system. Users can obtain the power states through an interface provided by the SMS.