Fractured-vuggy carbonate reservoir has the features of strong heterogeneity and complex structure，whose reservoir space is mainly large caves，solution pore and fractures. Gas flooding is one of the important methods of development in this type of oil reservoir. In order to probe dynamic features，influencing factors and rules of gas flooding in the fracturedvuggy carbonate reservoir，a typical 2D visual model of fracture-vug was built to study the development of remaining oil of various types. Physical simulation experiments of nitrogen gas flooding were carried out to study the influencing factors of the nitrogen gas drive. The research results show that the nitrogen gas drive can activate the remaining oil of unswept areas during water flooding. The effect of nitrogen gas drive and flow characteristics of oil，gas and water are influenced by cavityfilling type，crude oil viscosity and energy of bottom water. The cavity-filling type mainly affects the percolation characteristic of the fluid and is beneficial to enlarge swept volume of the nitrogen gas flooding to a certain extent. The crude oil viscosity and the energy of bottom water affect the interaction between the nitrogen gas and bottom water，which may change the distribution of pressure field. Bottom water with strong energy will accelerate water breakthrough，but it can improve the effect of the nitrogen gas drive and oil recovery.