Graphdiyne (GDY), a novel kind of two-dimensional carbon: allotrope consisting of sp- and sp(2)-hybridized carbon:atoms, is found to be able to serve as the reducing agent and stabilizer for electroless deposition of highly dispersed, Pd nanoparticles,owing to its lbw reduction potential: and highly conjugated electronic structure. Furthermore, we,observe that, graphdiyne oxide (GDYO), the oxidation form of GDY, can be used as an even excellent substrate for electroless deposition, of ultrafine Pd dusters to form Pd/GDYO nanocomposite that exhibits a high catalytic performance toward the reduction of 4-nitrophenol. The high catalytic performance is considered to benefit from the rational, design and electroless deposition of active metal catalysts with GDYO as the support.