There are a lot of options, and unfortunately you do not provide exact details of what is the "graph" in Excel (for instance, it may be a graph as an object on the sheet with data, or excel sheet itself), or what is the object in Word that you pasted. Also I guess that solution may depend on the Word/Excel versions.

Anyway, let us assume that in Word you have this graph as a "shape" object type msoPicture. Then you may use Shape properties and methods, like:

WITH  oWord.ActiveDocument.Shapes(1)
  .ZOrder(msoSendBehindText)
  WITH .Fill
     .Visible = .t.
     .Transparency = 0.2
  ENDWITH
  .TOP =150
   .width=.....
*  etc....
endwith

>Actually I can copy the graph on my clipboard and paste them in a Word document using the "PasteAndFormat" or "PasteSpecial" methods but I can't manage the image I pasted. I don't know how to move it or resize it in Word.
>I need to print the graph on a paper having a background picture and I don't know how to do it in excel.
>
>
>>>I can't understand how to manage a graph I pasted into Word.
>>>Word Macro seems to be unsensble to graph operation.
>>>What Have I to do ?
>>
>>It would help if you provide additional information, like, how did you paste,
>>as regular, or as a link, or special paste, etc...
>>Also, what do you want to do with the graph using Word Macro ?