Abstract: An ab initio and DFT theoretical study on the hetero DielsAlder reaction between 1,3butadiene and silyleneimine was presented. The structures of the reactants,intermediate complex,transition state and product were completely optimized by the Berny energy gradient technique at the HF/631G* and B3LYP/631G* theory levels, and the transition state was characterized by vibration frequency analysis. The reaction was found to be strongly exothermic and proceed in two steps:(1) Two molecules form an intermedi...