According to core observation, thin section identification and integration of well log and seismic data of Honghaoershute Sag, the Aershan formation lower segment, Aershan formation upper segment and Tenggeer formation first segment are rich in volcanic rocks, mainly consisting of andesite, volcanic breccia and tuff. Explosive facies, effusive facies and eruptive sedimentary facies can be identified, which are mainly effusive facies. The Mesozoic volcanic rocks in Honghaoershute Sag are distributed along big faults and superimposed by many times of volcanic eruption in the vertical. Three cycles and fourteen periods of volcanic eruption can be identified. The reservoir space consisted mainly of stomata and fracture. The major controlling parameters for reservoir quality are petrology, lithofacies and tectonic action as well as diagenesis.