We use SEM and EDX to study the structures and chemical compositions of feldspar surface silica glaze on Holocene volcanic eruptive material at the Tianwen peak, Tianchi, Changbai Shan. The result shows that there are silica glazes of varied structures formed on feldspar surface in the pumice that is black on the top and turns dark-grey downward on the cross section at the Tianwen peak. Their structural features depend on ages of volcanic eruption. Thick and complicated glazes are present on the pumice erupted earlier, while thin and simple glazes occur on the pumice generated later. It means that the form and thickness of glazes on feldspar surface are correlated with the time of volcanic eruption. These glazes are made up of Si (33.3~26.6%), Al (9.28~6.22%), Na (6.08~4.07%), K (3.84~2.35%) and Fe (3.82~1.64%). With increasing Si, the content of Al and Na tend to decrease, while that of K and Fe changes little. Such a composition indicates that the glaze resulted from deposits of dissolved silicate. And the correlation between the elements is analogue to that of the glaze rich in fragment determined by Dorn in 1998. The features of these structure and compositions are associated with the processes of rock weathering, migration and final deposit. And existence of element Fe is probably related with microorganism. Rock weathering, wore grain and dissolved ion provide the glaze formation with material sources. The detailed observations on glazes may be a new approach to study post-volcanic eruption settings and temporal process of volcanic eruptions from microstructures of rocks.