Combustion performance of Gasoline Direct Injection(GDI) Engine was tested while it was operated at several combustion chamber conditions. Two sets of injector and spark positions were examined, and curved (or bowl) piston was used for guiding the spray direction. When GDI engine was operated at the early injection condition, the evident differences of combustion performance according to the combustion chamber shapes could be observed. Using the visualized engine, we showed the spray processes and the proof of film combustion phenomenon. The difference of wetted fuel amount could be regarded as the reason of imep variation.