A power management method for a vehicle, the vehicle including an electrical system, a processor electrically connected to the electrical system, and a wireless communication module electrically connected to the processor, the electrical system including a power switch and a battery, the power management method to be implemented by the processor and including steps of: upon the power switch being switched from a conductive state to a non-conductive state, controlling the electrical system to temporarily supply the wireless communication module with electric power from the battery for establishing a wireless connection, and activating a timer to start timing; determining whether an elapsed time has reached a predetermined duration according to the timer; when it is determined that the elapsed time has reached the predetermined duration, controlling the electrical system to stop supplying electric power to the wireless communication module; and when it is determined that the elapsed time has not reached the predetermined duration, controlling the timer to stop timing and resetting the timer upon the power switch being switched from the non-conductive state to the conductive state; characterized in that: controlling the electrical system to temporarily supply the wireless communication module with electric power enables the wireless communication module to establish a wireless connection with a portable electronic device that includes a display unit; and the power management method further includes a step of controlling the wireless communication module to transmit a key-off signal to the portable electronic device so that the display unit displays a timing interface showing a timing result of the timer according to the key-off signal, and the timing interface indicates countdown of the predetermined duration. upon the power switch being switched from a conductive state to a non-conductive state, controlling the electrical system to temporarily supply the wireless communication module with electric power from the battery for establishing a wireless connection, and activating a timer to start timing; determining whether an elapsed time has reached a predetermined duration according to the timer; when it is determined that the elapsed time has reached the predetermined duration, controlling the electrical system to stop supplying electric power to the wireless communication module; and when it is determined that the elapsed time has not reached the predetermined duration, controlling the timer to stop timing and resetting the timer upon the power switch being switched from the non-conductive state to the conductive state; controlling the electrical system to temporarily supply the wireless communication module with electric power enables the wireless communication module to establish a wireless connection with a portable electronic device that includes a display unit; and the power management method further includes a step of controlling the wireless communication module to transmit a key-off signal to the portable electronic device so that the display unit displays a timing interface showing a timing result of the timer according to the key-off signal, and the timing interface indicates countdown of the predetermined duration.