Tahe fractured-vuggy reservoirs have a variety of residual oil，such as attic oil，inter-well oil，et al，after bottom water driving oil or water-flooding and replacing oil. In order to analyze the dynamic characteristics of gas injection huff and puff production and the influence of different gas injection medium on the recovery of light/heavy oil reservoir，the injecting water replace oil and injecting gas huff-and-puff was simulated with an indoor 3D physical model，which was designed based on the geological datum，the huff-and-puff effect of the three gas mediums（N₂，CO₂ and composite gas（N₂∶CO₂=1∶1））on residual oil was studied at the different viscosity of 1094.5 mPa·s and 23.6 mPa·s. The experimental results showed that the injecting gas huff-and-puff could control the bottom water and increase oil production obviously，N₂，and CO₂ could replace attic oil by the impact of gravitational differentiation，and flow around oil and inter-well oil could be carried by the impact of gas swelling. After N₂，CO₂ and composite gas huff-and-puff，the oil recovery for the heavy oil with the viscosity of 1094.5 mPa·s was enhanced by 19.59%，14.54% and 7.55%，respectively；while the oil recovery for the light oil with the viscosity of 23.6 mPa·s was enhanced by 10.87%，10.12% and 7.41%，respectively. The effect of injecting gas huff-and-puff for heavy oil was better than that for light oil under this experimental condition，and the effect of N₂、CO₂ huff-and-puff was better than that of composite gas（N₂∶CO₂=1∶1）.