GDI engine, with its excellent economical efficiency and transient response performance, has been widely recognized by the market. But the direct injection characteristics similar to diesel engine determines the short gasoline mixing time, fuel local rich and PM generation quality and quantity increasing. In addition, the oil inevitably involved in combustion will also affect the particulate emissions. In this paper, the particle size distribution characteristics of a GDI engine under different oil consumption conditions were measured by using DMS500 particle size analyzing instrument. The results show that the change of oil and gas separator state can significantly change the oil consumption of the GDI engine; Under idle condition, the quality and quantity concentration of particulate emissions will increase significantly with the increasing of oil consumption. Under low speed, low or middle load conditions, the quality concentration of particulate emissions will increase with the increasing of oil consumption. Oil consumption doesn’t have a significant influence on particulate emissions under middle speed condition.