AbstractFor a diesel engine, it is crucial and difficult to reduce the original particle matter emissions. Although the emission of particle matter can be reduced effectively, the engine internal purification and external purification measures can increase the cost and manufacturing process. Therefore, designing and improving oil products has become the most effective way to reduce emissions. This study compared the combustion and particle matter characteristics of diesel, diesel–rocket propellant-3 (RP3) (WDBF) with 20%, 40%, and 60% rocket propellant-3 in a single-cylinder compression ignition engine. The brake power, brake thermal efficiency (BTE), and particle matter concentration of the diesel engine were determined experimentally at three speeds (2,000, 2,700, and 3,600 r·min−1) at engine loads of 10%, 50%, and 100%. The results demonstrated that with the increase of the RP3 blending ratio, the density, cetane number, kinematic viscosity, and surface tension of diesel–RP3 WDBF decreased, whereas the low heating value increased, and T10, T50, and T90 (10%, 50%, and 90% volume distillation temperatures, respectively) decreased. The addition of RP3 to diesel increased the peak number concentration of small particles under the test conditions. The total particle number concentration (TPNC), total particle volume concentration (TPVC), and total particle mass concentration (TPMC) decreased by 14.1%–53.4%, 22.5%–75.3%, and 21.3%–39.3%, respectively, compared with that of using diesel. The change was obvious with the increase of the RP3 ratio and without impact on brake power and BTE.