A power management method applied in a portable electronic device is provided. When the portable electronic device enters a standby state, the method starts a frame refresh timer, wherein a timing period of the frame refresh timer is a frame refresh timing period; and starts a suspension timer, wherein a timing period of the suspension timer is a suspension timing period. When the portable electronic device is in the standby state, and when a frame refresh timing period of the frame refresh timer is completed, the portable electronic device displays one of the frames and sets the frame refresh timer to begin another frame refresh timing period for consecutively displaying the frames. When a suspension timing period of the suspension timer is completed, the portable electronic device suspends the frame refresh timer and enters a power saving state.