Jet-to-jet interaction in multi-hole direct-injection (DI) injectors of automotive gasoline engines have been concerned in recent years. In this study, one of the five jets issued from a five-hole DI injector was carefully studied using Phase Doppler Particle Analyzer (PDPA) and high speed imaging techniques. The tests were carried out in a constant volume vessel with absolute ambient pressure ranging from 0.05 to 0.5 MPa. Timeresolved development of the spray process is exhibited. The results show that the target jet was deviated towards to the injector axis in all the tested conditions. In addition, the spray at the sub-atmospheric and atmospheric ambient pressure exhibits more complicated process than those at the elevated ambient pressure. At subatmospheric and atmospheric conditions, the spray tip becomes obtuse and the droplet velocity at different radial positions shows a “double peak” velocity distribution inside the spray, rather than the “single peak” distribution at the elevated conditions. The droplet size distribution is also changed due to the jet-to-jet interaction. It is believed that the ambient pressure imbalance and the different nozzle exit velocity distribution resulting from the lower vapor pressure of gasoline account for the difference.