We e have studied the O2 dissociation barriers and O atoms adsorption energies of Ih M@Pd12, DI M2@Pd17, NW M4@Pd20 (M=Mn, Fe, Co, Ni, Cu, Pd) and show that the good ORR activity of NW M4@Pd20 (M=Mn, Fe, Co, Ni, Cu) which have small O2 dissociation energy (0.10~0.23 eV) and have small O adsorption energy (1.19~1.28 eV), there are two reasons summarized here, one is the number of the dope atoms increase from one to four, so the dope atoms would be make bigger effect to the surface Pd atomss d-band center, two is when the nanocluster became the periodic structure, the stability has been increased, and the structure relaxation which the O atoms adsorption induced will decreased, and make final energy increased.