I got the solution , actually it is very simple
<Fluent:Ribbon.Menu>
<Fluent:ApplicationMenu Header="Home">
<Fluent:MenuItem Header="Home Menu 1"
Icon="/packagename;component/Images/homemenu1.png" />
<Fluent:MenuItem Header="Home Menu 2"
Icon="/packagename;component/Images/homemenu2.png" />
</Fluent:ApplicationMenu>
</Fluent:Ribbon.Menu>
from this
link
thanks all for your valuable helps.