The ferromagnetic properties of Y-doped ZnO(0001)-Zn polar surface with and without point defects, including oxygen vacancy (V-o), hydrogen interstitial (H-i), and zinc vacancy (V-zn), are calculated using the first-principles method. Results show that Y-doped ZnO with or without V-o is nonmagnetic. H-i in Y-doped ZnO with V-o can combine adjacent O atoms to form a bound magnetic polaron. Adjacent H-O bound magnetic polaron (BMPs) create an interconnected BMP cluster, which induces the ferromagnetism of ZnO. Unpaired O-2p electrons induced by V-zn causes ZnO to have a long-range ferromagnetic order through the double-exchange mechanism. Ferromagnetic quenching occurs in the ZnO lattice when the ratio of Y to V-zn is 2:1. Both ferromagnetic mechanism can be achieved at room temperature.