How can i stop my kitten?

You can't. The safest and wisest thing to do is replace your breakable ornaments with ones that are shatterproof... at least on the lower branches. As long as there is a giant toy (Christmas tree) in her presence, she will want to play with it. I've tried everything you can imagine through the years and can ure you that a determined cat will not be deterred from the Christmas tree no matter how hard you try. You can spray her with water, shoo her, sprinkle/spray things on the tree and everything else but she'll still get into it when you're not looking if she really wants to. The only foolproof way to keep her out of the tree is to close it off in a room that she doesn't have access too.