My girlfriend which is maria mother is claming her do i still put her on my tax form

[LinaJ2018 · Accepted solution]

No.  If her mother is claiming her as her dependent on the tax return, you will not qualify and therefore do not include her on your tax return. 

[Hal_Al]

That answer is correct but assumes you and your girlfriend (GF) live together with the child.
If  you live apart AND the child lives with you, i.e. you are the custodial parent; the answer will be different.