An antenna unit, an antenna system and an antenna control method are disclosed. The antenna unit includes a first radiation metal element, a second radiation metal element, and a third radiation metal element. The first radiation metal element includes a signal feed point, a first ground point, and a second ground point. The signal feed point, the first ground point, and the second ground point are disposed approximately in a straight line. The second radiation metal element is disposed away from the first radiation metal element with a gap and includes a third ground point. The third radiation metal element surrounds the first radiation metal element and the second radiation metal element and includes a fourth ground point.