Point formPoint = this.PointToClient(Control.MousePosition);//鼠标相对于窗体左上角的坐标 int x = formPoint.X; int y = formPoint.Y; double xx=chart1.ChartAreas[0].AxisY.IntervalOffset; //你通过比例关系计算点的高度值信息,传给toolTip1即可 toolTip1.Show("xx"+xx, this, x, y);