Abstract: To understand the influence of n-butanol on the surface functional groups and oxidation activity of diesel engine particles, particle size sampling device was used to collect the diesel engine particles. Different n-butanol quality mixing ratios of 0, 5%, 10% n-butanol/diesel combustion particles（N0, N5, N10） were carried out the experimental study on the surface functional groups and oxidation activity by using the technique of soft X-ray near-edge absorption spectroscopy and so on. The results show that the surface functional groups of particles are mainly aromatic hydrocarbons C=C, C — H and carbonate/carbonyl C=O functional groups. Among these groups, the absorption peak of C=C bond is stronger. With the increase of n-butanol proportion, the absorption intensity of C=C bond is weakened. The PHAs and graphite carbon contents gradually reduce that are produced by incomplete combustion of fuel. The equivalent peak ratio(I_C-H/I_C=C) of aliphatic C—H groups of N0, N5 and N10 combustion particles are 1.7、2.2、2.6 respectively. With the increase of n-butanol ratio, the equivalent peak ratio increases, and the content of aliphatic C — H increases gradually. The activation energy of particles decreases with the increase of n-butanol proportion, and the oxidation activity of particles increases which is prone to oxidation combustion reaction.