The effects of petrochemical diesel fuels with different physicochemical properties on engine particle emissions were investigated under steady state and transient loading conditions. Regarding ignition performance, as the cetane number increased under low load conditions, the total particle number concentration and accumulation mode particle number concentration initially decreased and then increased slightly, while the nucleation mode particle number concentration continued to rise. Under medium and high load conditions, the number concentrations of both nucleationmode and accumulation mode particles increased gradually. During transient loading processes, the number concentration of total particles first decreased and then stabilized. In terms of evaporation performance, as the aromatic content increased under low load conditions, the number concentrations of nucleation mode and accumulation mode particles first decreased and then remained largely unchanged. Under medium and high load conditions and transient operating conditions, no significant changes were observed in the number concentrations of both types of particles.