Abstract: To reduce the oxidation temperature of diesel soot, the KNO3 and KOH supported nKCe0.5Mn0.5O2(n=005, 020 and 050) catalysts were prepared by citric acid solgel method. Thermogravimetric (TG) and temperature programmed oxidation (TPO) were used to investigate the effects of catalysts on the catalytic oxidation activity and stability of diesel soot. Xray diffractometer (XRD) was used to characterize the catalyst before and after the TPO experiment. The results show that the Ksupported catalyst can reduce the ignition temperature of diesel soot. The 050KOHCe0.5Mn0.5O2 has the best oxidation activity for soot under NO atmosphere among all catalysts. After TPO experiments for 10 times, the 020KNO3Ce0.5Mn0.5O2 catalyst still maintains high catalytic activity with good stability. The diffraction peak of KNO3 does not change, while the diffraction peak of KOH is disappeared, which proves the KNO3supported catalyst has excellent stability. By preparing a catalyst with suitable performance, the temperature required for diesel particulate filter(DPF)regeneration can be effectively reduced with decreased emissions.