Aiming at probing into the structure and composition sensitivity of transition metal carbides (MxCy) to catalytic performance of C2H2 selective hydrogenation, twenty-three kinds of MxCy (M = Ti, Zr, Hf, Mo, W and Co) catalysts with different M types, crystal facets and M: C ratios are investigated using DFT calculations and microkinetic modeling. The results show that C2H4 activity and selectivity depend on surface composition and structure due to the ensemble and/or ligand effects. Charge transfer number from M to C atoms and d-band center can be used as the descriptors to efficiently evaluate C2H4 selectivity and activity over MxCy catalysts, respectively. α-MoC(101) is screened out to exhibit Pt-like electronic properties with better C2H4 activity, selectivity, and catalyst stability to resist green oil formation compared to Pt and other MxCy catalysts when the temperature is ≤425 K and H2: C2H2 ratio is ≥1: 1, which is superior to the industrial PdAg/Al2O3 catalyst.