Is there a Microsoft Office 2007/2010 theme for LibreOffice? The interface of Libreoffice slightly confuse me.
It appears unlikely, if a quick Google search doesn't pick up simple things like themes for programs it's unlikely they exist without it requiring some substantial programming experience. Just use LibreOffice for a month and before long you will likely loose that confusion. If you want help with finding stuff in LibreOffice press 'F1' and use the help provided. Or you could just look through the menus under the headings, 'file' 'edit' etc. Good question though, I'm sure many have at least asked themselves that.
What you are searching for is a Ribbon style menu for LibreOffice, which doesn't exist yet. You can find an overview of all current design changes being worked on here.
There is an icon set for Libreoffice that looks like the icons of MS Office 2013: http://charliecnr.deviantart.com/art/Office-2013-theme-for-LibreOffice-512127527