Abstract: The present study mainly reports the effects of methanol blending ratio on carbon structure by laser Raman spectrometer and peak fitting. Blends of diesel with 0,5% and 15% methanol (designated here as M0, M5 and M15) were used in a non-road diesel engine. The oxidation curve of particles in O2 atmosphere and oxidation kinetics parameters were calculated to confirm the results of carbon structure analysis. The results showed that:1)The brake NO_x, CO, HC emission has obvious rise with the increase of methanol blending ratio, emissions generated by M15 were significantly increased by 12%, 49%, 62%, respectively. However, the brake particulate emission was significantly reduced by 59%. 2)Two strong and overlapping Raman peaks appeared at about 1350 cm^-1 and 1590 cm^-1, due to the stretching vibration between the carbon bonds in particles. Strong Raman peaks appearing at about 345 cm^-1 appeared with the increase of methanol blending ratio, which was probably because of the increase of the stretching vibration between carbon bonds in particles. 3)The relative strength of D3, which could be reflected by the amorphous components, and D/G reflecting graphitization degree increased along with the increase of methanol blending ratio, and the FWHM and relative strength of D1-D4, G also increased along with the increase of methanol blending ratio. The data confirm that as methanol use increases, the degree of graphitization in particulates decreases, the disorder of graphite structure increases, the amount of molecular carbon increases and the particulates can be oxidized more easily. 4)The oxidation experiment of particulates generated from diesel/methanol combustion also confirmed that the addition of methanol in diesel fuel is conducive to the oxidation of particulates, and shortening the regeneration time of particle in the filter body.