Sigh. Okay, I guess I read this the wrong way around. I thought you were trying to get newlines into your strings, and since that's exactly what you did, I was confused. It seems that what you actually want is to create grid boxes programmatically.
Per the documentation, Ctrl+Enter is equivalent to Add Row (http://reference.wolfram.com/language/ref/menuitem/AddRow.html). So, the answer to your question
Ctrl+Enter not equal \n ?
is yes, Ctrl+Enter is not the same as \n.
As for your other question,
How can I get a list as I wanted by codes not by Ctrl + Enter?
Maybe use FullForm to see what expression you've actually created. Then go read about low-level box structures. It's going to be much more complicated than "\n".
