I create a new list in SharePoint 2010 and start edit the form in info path and now I want to import part of the fields from other info path template( already exist) is that possible ?
this cannot be performed,
Infopath forms can only contain fields from the SharePoint list
something you can do is Add the section control and formatting rules to hide or show fields.
If you want to draw data from another list you have to create lookup fields.