Abstract: The internal flow and spray-wall impingement characteristics of circular and elliptical GDI orifices were simulated by the VOF-spray one way coupling method under different injection pressures. The results show that the mass flow rate of isooctane at the outlet of elliptical orifice is larger than that of circular orifice, and the mass flow rate of isooctane in elliptical orifice E2 with the aspect ratio of 4 is 3.54% larger than that of circular orifice under the injection pressure of 15.0 MPa. In the spray penetration stage, the spray penetration of elliptical orifice is always smaller than that of circular orifice, which delays the time when the spray impacts the wall. Under the injection pressure of 6.0 MPa, compared with the circular orifice, the spray impingement time of the elliptical orifice E2 is delayed by 0.14 ms. The impinged spray radius width and height width of the circular orifice are larger than those of the elliptical orifices after the impingement. This is because the circular spray has larger momentum, which promotes the splash and rebound of the impinged spray, while the difference between circular and elliptical orifices is decreased with the increasing of injection pressure.