Potential explosion hazards arising from releases of natural gas are now reasonably well understood, but the hazards exhibited by vapor-liquid two-phase ( mist) mixtures are often overlooked. This work aims at providing new experimental data on the influence of the particle size of liquid phase n-heptane on the explosion parameters in vapor-liquid two-phase n-heptane/air mixtures. A series of experiments was carried out as follows: First, at the mean Sauter mean diameter of 12.16 mu m and 21.23 mu m, two sets of vapor-liquid two-phase n-heptane/air mixtures of various concentrations was obtained. Subsequently, experiments were implemented on the explosion pressure and the explosion temperature on two sets of various concentrations of the vapor-liquid two-phase n-heptane/air mixtures. The lower flammability limits and the minimum ignition energies were analyzed.