In gasoline direct injection engines, predictions of the spray formation process and mixing process are required to improve both the fuel consumption rate and exhaust gas emissions. Numerical analysis of these processes using a swirl-type injector has been performed. The effects of injection speed profile and initial injection quantity, which has no tangential momentum, on the above processes are investigated by employing different breakup models for the liquid sheet region and its downstream region. As a result, the decrease in the injection speed at the end of injection duration enables the reproduction of droplets along the spray center-axis while the initially injected spray affects the spray profile.