Abstract: Huagang Formation and Pinghu Formation are the most important producing pay in F1 Block of Pinghu Field, the East China Sea, and Pinghu Formation is the main gas producing zone. As the field comes to the decline period, searching for potential capacity in deep zone plays more important role recently. The article is based on large amount of routine core analysis data, correlation with well logs and well test analysis. Under the interpretation of the lithologic properties, pore microscopic texture and physical properties, we summarize that the characterstics of P11 is different from conventional reservoir. After study the relationship of P11 characteristics with diagenetic metamorphism, clay mineral, abnormal pressure, grain size, core formation, we think they are the main controlling factors of P11. At last we think sand extent area, abnormal pressure area and reservoir protection will be important to gas exploration and development in this area.