In the combustion chamber of a spark-ignition direct injection (SIDI) engine, effective mixing between fuel spray and in-cylinder air is an important criterion in improving the combustion efficiency and reducing the emissions. Effective fuel atomization could further enhance the fuel-air mixture by promoting the interaction of liquid fuel with the surrounding air flow. In this research, a novel high-speed two-color PIV (Particle Image Velocimetry) technique is developed and applied to simultaneously measure the velocity flow-fields of a multi-hole fuel injector spray and its surrounding air in a high pressure constant volume chamber. To allow for the phase discrimination between the fuel droplets and ambient air, a special tracer-filter system was designed. The interactions between the superheated fuel spray and the surrounding air is analyzed for both 2-hole and 6-hole fuel injectors under various ambient pressure and fuel temperature conditions.