if i uninstall itunes and reinstall it will i lose my all music

No. Back it up anyway.

(71569)

Upgrading will normally not affect the tracks and settings already in your iTunes. That said, it's wise to make a backup of any content that you've purchased from the iTunes Store or that would otherwise be difficult to replace and of your playlists before you upgrade, just in case something would happen to go wrong. While it's usually possible to re-download content from the iTunes Store, it's not always so.

Regards.