This study investigated experimentally the effects of fuels stratification of Di-methyl Ehter (DME) which has large heat release in LTR and n-Butane which has smaller heat release in LTR than DME on Homogeneous Charge Compression Ignition (HCCI) combustion. With the four stroke single cylinder optical accessible engine, in addition to pressure measurement, chemiluminescence imaging was used as a means of visualizing stratified charge and evaluating local combustion characters. In some mixing methods, stratified charge reduced the maximum pressure rise rates during HCCI combustion. Chemiluminescence images showed that stratified charge, comparing to homogeneous charge, dispersed the start time of chemiluminescence.