1. An intelligent entrance guard unlocking system comprising: a power unit of an intelligent entrance guard; a current transmitter of the intelligent entrance guard electrically coupling the power unit with a transmitter coil, and configured to receive electric energy supplied by the power unit, wherein the current transmitter transmits the electric energy by wireless electromagnetic radiation via the transmit coil; a first storage unit of the intelligent entrance guard storing a predefined vein image; a first controller of the intelligent entrance guard coupled to the first storage unit; a wireless receiver unit of the intelligent entrance guard coupled to the first controller; an unlocking unit of the intelligent entrance guard coupled to the first controller; and a powerless smart key comprising: a receiver coil; a current receiver electrically coupled to the receiver coil, and configured to receive the electric energy via the receiver coil such that the powerless smart key is powered; a vein recognition unit coupled to a second storage unit, and configured to capture a vein image of a part of a user via a number of small cameras by Infrared scanning technology and filter noises from the vein image to get a filtered vein image and further store the filtered vein image in the second storage unit; and a second controller coupled to a wireless transmit unit with the second storage unit and configured to control the wireless transmit unit to transmit a wireless signal containing the filtered vein image; wherein, the wireless receive unit receives the wireless signal, and the first controller is configured to obtain the predefined vein image from the first storage unit and compare the filtered vein image with the predefined vein image, and the unlocking unit is configured to unlock the intelligent entrance guard when the filtered vein image matches with the predefined vein image, and not unlock the intelligent entrance guard when the filtered vein image does not match with the predefined vein image.