C4F7N gas is one of the most promising environmentally friendly insulating media to replace SF6 gas. In practice, the internal discharge of high-voltage insulated electrical equipment will cause gas decomposition and endanger the safety of the equipment and personnel, so it is urgent to carry out research on the adsorption performance of commonly used adsorbents on the decomposition products of the new environmentally friendly insulating gas C4F7N, in order to provide a theoretical basis for the search for a suitable adsorbent. HKUST-1(Cu) is a typical metal-organic framework (MOF) material with broad application prospects in the selective adsorption of gases. It is a typical metal-organic framework (MOF) material with a broad application prospect in selective gas adsorption. In this paper, based on the density functional theory, the molecular simulation software Materials Studio was used to construct the molecular models of C4F7N decomposition of the harmful gas C3F6, CF3CN and the adsorbent HKUST-1(Cu), and analyse the adsorption effect of HKUST-1(Cu) on C3F6 and CF3CN. The simulation results show that HKUST-1(Cu) mainly adsorbs CF3CN, and the adsorption effect on CF3CN is significantly stronger than that on C3F6, and it can be used as an adsorption material for CF3CN, a harmful product of C4F7N decomposition.