Disclosed is an electromotive sunvisor assembly of a vehicle and a method thereof in which a visor body is automatically movable to the outside of an overhead storage room and can be pivoted at a moving shielding site. The electromotive sunvisor assembly of a vehicle comprises an upper guide bar and a lower guide bar. An upper driving member is glidingly disposed at the upper guide bar. A lower driving member is glidingly disposed at the lower guide bar. A rotary shaft is extended from the lower driving member in a lateral direction. A mounting bar is rotatably disposed at the rotary shaft and a visor body is fixed thereto. A rotational operation slat is formed protrudently from the mounting bar. A link is axially connected to one side of the upper driving member and the other end thereof is axially connected to the rotational operation slat.