There's a danger in trying to translate this literally since it's actually a phrase denoting a commercial name, with a few words left out but generally understood. The full meaning is: "Cerveza Negra by Modelo"; in English "Black (dark) Beer by Modelo (brewery)".
It means black model but the syntax is wrong. Modelo (model) is a masculine noun so it should be either "Modelo negro" for black male model or "Modelo negra" for black female model.