To maximize the engine drive-ability and minimize the exhaust emission levels, oil companies have cotrolled the fuel distillations depending on the seasons and fuel distributed areas, but there is a possibility that the HCCI combustion characteristics change because of the c hange of the fuel composition. Though the crank angle at 50% burn(CA50), which is an important parameter to reduce unburned hydrocarbons, can be mechanically controlled, the mechanical controlling of high temperature heat release combustion period is difficult. The improvement of combustion characteristics from the standpoint of fuel composition is a purpose of this paper, and the interaction between fuel compositions and heat release patterns were fully investigated.