Dye-sensitized solar cells(DSSCs)have been considered as an alternative to silicon-based solar cells.However,the counter electrode is usually using Pt which is very precious.Graphdiyne is a new two-dimensional carbon material,which exhibits promising catalytic ability.Herein Density functional theory calculation is used and reveals that the structure of Pt nanoparticles-graphdiyne nanosheet (PtNPs-GDNS) is beneficial to improve the catalytic ability and electron transfer as counter electrodes for DSSCs because the interaction between Pt and C is formed via the dz2 orbital of Pt and pz orbital of C.