Three-dimensional penetrating Pt-loaded mesoporous Cr₂O₃ catalysts (Pt@M-Cr₂O₃) were synthesized by pyrolysis of MIL-101-Cr containing pre-impregnated Pt NPs. Physicochemical properties of the samples were characterized by means of various techniques including XRD, Raman, BET, SEM, TEM, XPS and H₂-TPR, and their catalytic activities were evaluated by toluene combustion compared with commercial Cr₂O₃ (C-Cr₂O₃). It is found that mesoporous Cr₂O₃ (M-Cr₂O₃) support with a high surface area of 77.40 m2/g is composed of vast Cr₂O₃ nanocrystallites. With pre-impregnated Pt loading in MIL-101-Cr, it partly restrains the aggregation of Pt NPs during the pyrolysis of MOFs to M-Cr₂O₃ and strengthens the interaction between Pt NPs and Cr₂O₃ nanocrystallites. The obtained 0.82Pt@M-Cr₂O₃ exhibits the best catalytic performance of toluene combustion, giving 120, 140 and 144 °C of T10%, T50% and T90% under 1000 ppm of toluene at space velocity of 20,000 mL/(g h), respectively. The investigation of the different space velocity, the catalytic stability and the effect of water vapor on catalytic activity over 0.82Pt@M-Cr₂O₃ have confirmed the good catalytic performance. Furthermore, the studies of in situ DRIFTS indicate toluene degradation over 0.82Pt@M-Cr₂O₃ is via benzoate species by rapidly transforming of benzylic and aldehydic species, and then oxidized to maleic anhydride in an aromatic-ring opening reaction, finally is decayed to CO₂ and H₂O.