N-butanol is a promising alternative fuel for automobile whose explosion characteristics should be a major focus before widely used. Unfortunately, limit researches focusing on its explosion characteristics have been launched until now. In this study, the effects of n-butanol addition on the explosive characteristics of iso-octane-air mixtures with various concentrations and initial pressures and temperatures were experimentally investigated and analysed on the basis of combustion pressure history. The explosion pressure p(exp) and the maximum explosion pressure p(max), the maximum rate of pressure rise (d(p)/d(t)) max, the deflagration index K-G, and combustion duration t(c) as well as flame development period t(d), were examined. Results show that with the increase of n-butanol blending ratio, explosion pressure does not change, while explosion duration is decreased, so the maximum rate of pressure rise is increased. It was found that pressure curves of rich mixtures oscillate in the vicinity of pressure peak at elevated pressures, and the pressure oscillation greatly shortens the explosion duration and increases the maximum rate of pressure rise. In addition, with the increase of n-butanol blending ratio, the pressure oscillation intensity is decreased. (C) 2016 Elsevier Ltd. All rights reserved.