The discovery of bioclastic and grit beach facies reservoirs in the PG6 well, and oolitic beach facies reservoir in 302-1 well, shows that the Puguang gas field Changxing Formation develops both reef and beach reservoirs. In the late period of Changxing Formation, the facies of Puguang gas field evolved into platform edge, developed reef and shallow facies. With the recognization of reef and shallow facies in development wells by type clustering, the reef is scattered around wells PG5, PG6, PG8, PG9, MB3, etc, the shallow facies is scattered around wells PG2, PG4, PG6, PG7, 102-1, 302-3, 302-1, they extend narrowly, and have a northwest\|eastsouth direction. The Changxing Formation reservoirs are mainly a set of reef dolomite, sparry oolitic dolomite, and have moderate to high porosity, moderate to high permeability and good physical properties. The reservoir space types are mainly intercrystalline pore, intercrystalline solution pore, intergranular dissolved pore, intragranular dissolved pore, moldic pore and dissolved expanding pore, and to a lesser extent, crack and suture. The Changxing Formation reef and shallow facies reservoir is a new type of reservoir having a great potentiality after Feixiaguan Formation oolitic beach was found.