The reaction mechanism of the Propargyl radical and Nitrogen oxide has been studied by the Density Functional Theory (DFT) using the B3LYP functional in conjunction with the 6-311++G(3df,2p) basis set. The potential energy surface (PES) for the C3H3 and NO system was also established. Calculated results indicate that products of this reaction may be (HCCCN+H2O), (C2H2+HCNO), (HCCCNO+H2), (HCN+H2CCO), (HNO+H2CCC), (H2CCCN+OH), (H2CCH+CNO), (H+HCCCHNO), (CN+H2CCOH), (C2H+H2CNO), (CH3+CCNO), (CH3+OCCN), (H2C+HCCNO), (H2CCO+HNC) and (C2H2+CNOH). However, the formation of (HCN+H2CCO) is the most favorable.