Abstract: In order to reveal the explosive risk and the changes on explosion characteristics of premixed gas under different ambient temperatures, the explosive pressure characteristics, combustion characteristic parameters and explosive limits were tested in 20 L explosion characteristic experimental device which were heated through interlayer and inner cavity by using high voltage discharge at different ambient temperatures(20 to 200 ℃). The research showed that the maximum explosion pressure, explosion reaction time, and ignition delay time all gradually decrease with the increase of ambient temperature under experimental conditions.The maximum explosion pressure decreased by 43.8%, while the explosion reaction time and ignition delay time reduced by 54 ms and 14.4 ms respectively, when the ambient temperature rose to 200 ℃. The pressure rising rate was unobviously affected by temperature. As the ambient temperature increases, the intramolecular energy increases, the easier the stable non-combustible system becomes an explosive system, while the explosion limits range becomes wider.