Homogeneous Charge Compression Ignition (HCCI) engines could offer low NOx, PM emissions and high efficiency. However the operation region is limited because of knocking and misfire. Moreover the HCCI principal lacks direct combustion control and needs a system to control the combustion phasing with high accuracy. Cyclic dispersion is also a big problem in HCCI combustion. Today there exists various ways to control the HCCI combustion but these systems are heavy and complex. In this study, in order to develop a small and light HCCI engine, a simple HCCI combustion control system is proposed. DME (Di-methyl Ether) is used as a fuel to keep the structure small and light. This system uses throttles to change the mixing ratio of stoichiometric pre-mixture. hot EGR (Exhaust Gas Recirculation) gas and cold EGR gas. With this system, combustion control concept is evaluated and characteristics of cyclic dispersion are analyzed experimentally. Moreover, based on these results, reduction of cyclic dispersion is attempted by combustion control.