Majiagou Group gas reservoir is a large palaeogeomorphology-lithologic gas reservoir relevant to ancient karst or unconformity of the top Ordovician in Jingbian gasfield western region. The coexistence of pre-Carboniferous palaeogeomorphology platform, trenches, pits controls reservoir distribution and gas migration and accumulation. Hence, the accurate recovery palaeogeomorphology is the key to reveal the size of the gas reservoir of Majiagou Group. In this paper, it is to analyze from regional geological setting of the gas reservoir, geological, geophysical characteristics by drilling practice test, the technical series has the industrialized production capacity, and has an important role in submitting proved reserves of Majiagou group gas reservoir and selecting well location in Jingbian gasfield.