Pt catalysts for PEMFC were prepared by microwave-sol process,which was a new efficient way to prepared nano materials.Tests of BET,XRD,TEM and PEMFC electrochemistry work station were adopted to analyze the relationship between synthesis way,crystal structure and Pt catalytic capability.The results showed that the samples prepared by microwave-sol process had more BET surface areas and pore size distributions,while the sizes of Pt particle were decreased,and the useful crystal for O2 reduction were increased,too.The crystal transformation improved the electrocatalytic activity of Pt,and as a result,improved the performance of PEMFC.