Abstract: A series of Mn1-xAgxCo2O4 spinel oxide catalysts were prepared by sol-gel method and characterized by XRD，FI-IR，O2-TPD, and TPO techniques. The performance of the catalysts was evaluated in a home-made device by temperature programme. The results showed that the as-prepared catalysts possess spinel structures and exhibit high catalytic activity for soot combustion. Mn0.6Ag0.4Co2O4 catalyst has the best activity with a T50（the temperature at which soot conversions is 50%）of 325 oC, 260 oC lower than the temperature needed in non-catalytic soot combustion.

Key words: sol-gel method, spinel oxide, catalytic, soot, combustion