Abstract： This paper aimed to investigate the impact of fuel properties(T90 temperature and ethanol blended), engine operating parameters (load condition, spark timing etc.), and injection strategies (start of injection, split injection) on particulate size distribution and particle number. The experimental results show that T90 temperature has a significant influence on PM emission, and a low T90 temperature reduces PM emission. Particle number reaches the highest concentration at midload condition and decreases at highload because of oxidation in the high temperature exhaust and high rail pressure. E10 produces lower PM emissions. In general, advance injection timing affects fuel evaporating and mixing process and reduces PM emissions. Split injection  also reduces PM emissions and can be optimized to a lower level. As the  ignition timing is delayed, the formation of particles significantly is decelerated.