【正文】 ncy and reduced emission. HCCI bustion can not only ensure both the high economic and dynamic quality of the engine, but also efficiently reduce the NOx and smoke emission. Moreover, one of the remarkable characteristics of HCCI bustion is that the ignition and bustion process are controlled by the chemical kinetics, so the HCCI ignition time can vary significantly with the changes of engine configuration parameters and operating conditions. In this work numerical scheme for the ignition and bustion process of DME homogeneous charge pression ignition is studied. The detailed reaction mechanism of DME proposed by American Lawrence Livermore National Laboratory (LLNL) and the HCT chemical kinetics code developed by LLNL are used to investigate the ignition and bustion processes of an HCCI engine fueled with DME. The new kinetic mechanism for DME consists of 79 species and 399 reactions. To consider the effect of wall heat transfer, a wall heat transfer model is added into the HCT code. By this method, the effects of the pression ratio, the fuelair equivalence ratio, the intake charge heating, the engine speed, EGR and fuel additive on the HCCI ignition and bustion are studied. The results show that the HCCI bustion fueled with DME consists of a low temperature reaction heat release period and a high temperature reaction heat release period. It is also founde