Recently, the important issues of gasoline engine are to reduce the fuel consumption and emission. Thus, many researchers are studying the technology to solve these problems. One approach of these issues is to achieve homogeneous charge combustion and stratified change combustion with various injection strategy. In this study, the combustion characteristics of DISI engine accrding to injection strategy were examined. The effect of injection timing on lean limit A/F were investigated using dual DISI single cylinder. The results show that the engine operation region of dual DISI type engine is larger than that of PFI and DISI type engine cases. Especially, late injection is very effective to extend the operation region more than any other injection timings. In addition, the results show that when the DISI injection ratio is increase, leam limit A/F is improved. It means that the dual injection system car meet with emission regulations and reduce the fuel consumption. Also, combustion pressure of dual injection system is much higher than PFI and DISI injection.