First-principles computations were performed to investigate the catalytic oxidation of CO on Ti-anchored Ti2CO2 monolayer, a typical MXene. Ti2CO2 monolayer could prevent the formation of Ti clusters. Both Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) mechanisms were considered, and the results manifest that Ti-anchored Ti2CO2 monolayer exhibits very high activity even comparable to many noble metal catalysts for low-temperature CO oxidation. This work contributes to design more effective and nonprecious-metal single-atom catalysts and widen the applications of MXene-based materials.