Natural gas flooding is an important means to enhance oil recovery in tertiary oil recovery. The dynamic monitoring and evaluation of oil reservoirs before and after flooding is of great importance. Compared with water flooding reservoirs, the phase change of injection medium in natural gas flooding reservoirs is prominent, which makes it difficult to select instruments and interpret data. During the testing process, there are not only test safety risks such as high pressure, inflammable and explosive, and corrosion, but also the presence of natural gas hydrate increases the risk of wellbore obstruction of test instruments. The pilot test of natural gas flooding was carried out in the IV oil Group of the third member of Shahe Street in the north area of Liuzan Oilfield, Nanpu depression. Through the preliminary establishment of the dynamic monitoring system of medium and deep gas injection development reservoir, the miscibility of the injected gas formation was determined, the gas injection advancing edge was evaluated, the gas injection channeling and the plane dominant direction was determined. It satisfied the evaluation and optimization adjustment requirements for gas injection development in medium and deep oil reservoirs, and plays a crucial role in improving oil recovery.