how to create label depend the output of the program?

 if (a1.Contains(line))
                      {
                            Label one = new Label();
                            one.ForeColor = Color.White;
                            one.Text = line;
                            one.Left = 633;
                            one.Top = 250;
                            this.Controls.Add(one);
                     }
above code have no issue, it will add more label on your form but at same location. First you should understand this line
this.Controls.Add(one);
it means that, we are adding one label control to form control. So whether you want multiple label this code will work but in form you should set some systematic pattern for displaying those labels.

i tried this, one doubt.
in my project, just see this..
 if (a1.Contains(line))
                        {
                            Label one = new Label();
                            one.ForeColor = Color.White;
                            one.Text = line;
                            one.Left = 633;
                            one.Top = 250;
                            this.Controls.Add(one);
                          }
here a1 is the arraylist and line is some string, so actually this string check with this arraylist, if that line in the  arraylist, i have to print that,so if more string match with this arraylist have to create more label for print....
so what will print that?
                

                       

will this code create label dynamically?

If i am not wrong, then you want dynamically add label control on your form. May be below code will help you
Label lblNewLabel = new Label();
lblNewLabel.Name = "lblNew";
lblNewLabel.Text = "Hello";
lblNewLabel.Left = 250;
lblNewLabel.Top = 250;
this.Controls.Add(lblNewLabel);