Structures,stabilities,and magnetic properties of Pt_n(n=1-9) are calculated with generalized gradient approximation functional BPW91 and three-parameter hybrid density functional B3LYP in density functional theory.The methods give same stable structures and same lowest-energy structures but different stable order of sub-stable structures.Average coordination numbers and average bond lengths in two methods have similar patterns.They increase with cluster size,and have a great increase at n=2-3 and a small increase at n=4-9.Analysis of energies by two methods show that there are greater values at n=2,5,8,which illustrate that corresponding clusters have high stabilities.Study of Pt clusters indicates that average magnetic moment oscillates with cluster size.It has a gradually decrease trend.It shows that two methods can describe structures,stabilities and magnetism of clusters.