This is a slightly odd place. It's in the middle of a commercial area, with no restaurants in sight. If you get to the right block, it's actually behind a large building. You have to knock and be let in like a speakeasy.
Once inside, it's a pretty normal expat locale. The first floor is a Spanish restaurant, supposedly with one of the only wood-burning pizza ovens in Xi'an. Downstairs is the real Green Molly, an Irish pub. You can also order food here. The pizza was disappointing, but the Caprese salad and potato skins were outrageously good.
Green Molly is 200 meters north of Ginwa Shopping Center on the intersection of Gaoxin Road and Keji Road. It is behind the GAOKE building.