The volcanic reservoir in the Changde area in Songliao Basin consist of ignimbrite and tuff, most of which belong to acidic volcanic rock, and is very different from other volcanic reservoirs of oil and gas basin in China. The rock is generally compact in structure and texture. Structure cracks and corrosion caves can be observed in drilling cores, with dissolved holes seen locally. Various types of reservoir space can be found under microscope, including intragranular dissolved pores, intra-crystal pores, structural microcracks, cracks and contraction joints and others. The volcanic rocks are generally thin, with about 75 m of the biggest thickness in the volcanic rock of Fangshen 9 well. In addition, the Fangshen 9 well shows an explosive facies, while other places show effusion facies. Volcanic rocks in the study area are low-porosity, low-permeability reservoir, and its lithology and lithofacies are closely related to physical properties and control the formation of the primary porosity. Late diagenetic reformation, including tectonic activities and dissolution determines the degree of development of secondary pores. Fractures produced by tectonic movement are the important factor to improve reservoir quality, while the late filling destroys the capability of reservoir and accumulation. The superimposing areas between eruption and effusion facies near volcanic crater are the favorable target for gas exploration.