I have a live in girl friend. I would like her to leave. She refuses, what are my options?

What state?
Do you own or rent?
How long has she been there?
Has she paid any rent, does she buy the groceries, are there any arrangements?
Chances are you will have to go through a formal eviction of a tenant at will according to your state tenancy laws, or possibly be able to treat her as a lodger, who will have fewer rights. If she is destructive or violent, you call the police and get a RO.