A variable fender garnish structure of a vehicle is provided and includes a fender garnish coupled to an outer edge part of a wheel guard of a vehicle and made with a shape covering a wheel of the vehicle, a flap member positioned in the rear part of the fender garnish and rotatably coupled to the fender garnish, a driving member rotating the flap member, and a controller driving the driving member to control whether the flap member is rotated or not.