Abstract: A 3-D CFD simulation model of the ZR180 single-cylinder diesel engine was established based on CONVERGE software to study the effect of different combustion chamber shapes,intake port shapes and injector positions on the engine working state and combustion characteristics when the engine run gasoline early injection compression ignition mode. The calculation results show that the intake air flow has a significant impact on the working state of gasoline early injection compression ignition engine. Compared to the helical intake port,the tangential intake port makes the engine in transition operation state,leading to a 13% reduction of the indicated mean effective pressure（IMEP）. The shallow basin type combustion chamber presents 85% higher of the peak heat release rate and 120% higher of the peak pressure rise rate than the ω combustion chamber,respectively,due to the low temperature environment in the squish area of the ω combustion chamber. At the same time,the ω combustion chamber with higher surface-to-volume ratio can be used to increase the temperature stratification in the cylinder to enlarge the load,but the IMEP is reduced. It is also found that the combustion characteristics under the early gasoline injection are not sensitive to the injector position.