Smart Welcome System of Vehicle and Controlling Method Thereof

A control method of a smart welcome system of a vehicle includes emitting a low-frequency signal of a first power to search for a smart key in a first search area, emitting a high-frequency signal by the smart key, determining that the smart key is within the first search area, carrying out authentication for the smart key, transmitting a wake-up signal to an AVNT smart connection device, and emitting a low-frequency signal of a second power to search for the smart key in a second search area, executing a booting program, transmitting a high-frequency signal by the authenticated smart key, determining that the authenticated smart key is within the second search area, unfolding a side mirror and outputting a welcome sound output signal to a welcome speaker, and outputting a welcome sound simultaneously with unfolding the side mirror.