All the possible geometry structures of Pt_nNi_m (n＋m＝7, n, m≠0) clusters are optimized by density functional theory (B3LYP) at the LANL2DZ level. Their ground state structures are obtained from structures optimization and its stability and magnetism are studied. The calculated results show that all the ground state structures of Pt_nNi_m clusters are cube structures, whose symmetries is lower and multiplets is higher. Pt₅Ni₂ is the most stable one of Pt_nNi_m clusters. From magnetic analysis, we can see the total magnetic moment of Pt₂Ni₅ cluster is the largest, while the Pt₅Ni₂ cluster is the smallest. Local magnetic moments of the atoms at the symmetrical position are equal, and Ni atom plays a leading role in magnetism of the binary Pt_nNi_m clusters.

Key words: Pt_nNi_m (n＋m＝7, n, m≠0) cluster, structure and stability, magnetic property, density functional theory