The reaction mechanism of the oxyzen (O) atom and benzyne (C6H4) has been studied by the Density Functional Theory (OFT) using the B3LYP functional combined with the 6-311 ++G(d,p) and 6-311+G(3df,2p) basis sets. The authors have mapped out the potential energy surfaces (PES) for the C6H4+O system and the results show that energetically allowed paths lead to the product sets of CSH4+CO, C6H2+H2, C6H3+H, HCCO+C4H3 and C2H2+C4H2O. However, the formation of CSH4+CO is the most favorable process, with no exit barrier. The predicted barrier free channel indicates this reaction to be a fast process.