The processes of oxidation and weight loss for the particles produced in EGR atmosphere of diesel engine were researched by using thermogravimetry and the effects of EGR rate, EGR exhaust gas component and EGR temperature on particulate oxidation activity were analyzed. The influences of oxidation atmosphere parameters such as different atmospheres and heating rates on particle oxidation process were investigated. The results showed that the content of SOF component increased, the soot content decreased, and the weight loss rate increased at low temperature weight loss area, decreased at high temperature weightlessness zone and its corresponding peak temperature increased with the increase of EGR rate. When the EGR rate was constant and the EGR exhaust gas temperature was increasing, the oxidation property of particle deteriorated with the increase of reaction temperature. When the EGR components were different, the particles produced in the CO₂ cycle had faster weight loss rate, lower reaction temperature and easier oxidation property than those produced in exhaust or nitrogen cycle. With the increase of heating rate, the particle weight loss rate had little change, the oxidation reaction delayed and the characteristic point temperature increased. In addition, the oxidation property of particle deteriorated with the increase of heating rate.