This Study is to analyze the characteristics of arson fire under fire dynamics to protect people and property from arson fire which has been radically increased with the development of the Korean economy. Assembly and merchandise purposes such as theater, retail, and exhibition has been performed as the arson fire study. The experiment for this study is based on the analysis of the characteristic for its own combustion process and smoke spread when arson fire occurs. This study presents the analysis through comparing the condition of setting fire using liquid fuel such as thinner on purpose to the condition of setting fire naturally depending on each occupancy.