在pictureBox的Paint事件中写下如下代码

private void pictureBox1_Paint(object sender, PaintEventArgs e)

        {

            foreach (Control C in this.Controls)

            {

                if (C is Label)

                {

                    Label L = (Label)C;

                   L.Visible = false;

                    e.Graphics.DrawString(L.Text, L.Font, new

          SolidBrush(L.ForeColor), L.Left - pictureBox1.Left, L.Top - pictureBox1.Top);

                }

            }

        }

或者在载入页面的时候在LOAD中写入下面代码：

pictureBox1.SendToBack();

            label1.BackColor = Color.Transparent;

            label1.Parent = pictureBox1;

            label1.BringToFront();