Melt structure plays an important role in governing physical and thermodynamic characteristics of magmas. Exemplified by Jingpohu Holocene volcanic rocks, this paper has discussed the relationship between melt structure and volcanic eruptive mechanism. The NBO/T values (the non-bridge oxygen numbers per unit of cations) are calculated on the basis of the concentrations of major elements and volatiles. The results show that the proportion of lava in the total eruptive volume and its flowing capacity increase with increasing NBO/T values. The lava with high NBO/T values is liable to generate the lava channel. Volatiles such as H2O and F are likely to concentrate in magma with high NBO/T values.