Based on the macroscopic and microscopic research, the present paper focus on development and formation of high-quality reservoir, features of reef-shoal reservoir of Changxing Formation in Yuanba gas field are researched and the characteristics are concluded. The reservoir of Changxing Formation in Yuanba area was controlled by sedimentary facies, tectonic movement and diagenesis, and affected by the double action of predeposit palaeogeomorphology and post-Yanshanian movement. The physical properties of reservoir are better in the west than in the east. Three-stage fracture and dissolution are the key factors for the reservoir formation.