HFO-1336, a new environmentally friendly insulation gas, is highly regarded for its extremely low global warming potential (GWP) and excellent thermal stability. However, HFO-1336 can produce hazardous decomposition products at high temperatures or under certain conditions, and these decomposition products pose potential threats to equipment and the environment. Therefore, it is important to screen efficient adsorbent materials to deal with these harmful decomposition products. In this study, the adsorption performance of Co-MOF-74 and Ni-MOF-74 on C2F6 and CF4, the main decomposition products of HFO-1336, was simulated using Material Studio software. The results showed that Co-MOF-74 exhibited higher adsorption capacity in adsorbing C2F6 and CF4, especially in the multicomponent adsorption isotherm, where the adsorption capacity of C2F6 was significantly larger than that of CF4 and tended to be saturated after 60 kPa. In contrast, the adsorption amount of C2F6 in the single-component adsorption isotherm of Ni-MOF-74 was smaller than that of CF4, but in the multicomponent adsorption isotherm, the adsorption amount of C2F6 was significantly larger than that of CF4, indicating that the adsorption of C2F6 by Ni-MOF-74 inhibited the adsorption of CF4. The results show that Co-MOF-74 has excellent performance in terms of adsorption amount and selective adsorption performance, which is more suitable to be used as an adsorbent for HFO-1336 electrical appliances, and provides strong technical support for the wide application of new environmentally friendly insulating gases such as HFO-1336.