Ultra-deep carbonate gas reservoirs are deeply buried，with complex stress states and extremely strong heterogeneity，and the change laws of pore and throat structures before and after stress changes is not clear. In this paper，the cores from Deng4 gas reservoir in Gaoshiti-Moxi block were selected，and CT experiments were conducted to obtain the size distribution of pores and throats，the proportion of pores and vugs，and the connectivity of various reservoirs before and after the stress experiment and fracturing experiment. In addition，the effects of stress and fracturing on the pore and throat structures of ultra-deep carbonate reservoirs were studied. The research results reveal that the pores and throats in the pore-vug and fracture-vug cores decrease obviously after recovery from stress，and most of them are the micropores and mesopores with a radius of less than1 mm and the micro-throats with a radius of less than 0.04 mm. The average pore radius，average throat radius，average throat length，as well as the proportion of fractures and vugs all rise significantly，while the total volume of pores and throats tends to decline. The volume ratio of connected pores and throats in the pore-vug cores decreases significantly，while the volume ratio of connected pores and throats in the fracture-vug cores remains at the original level due to the development of fractures. After fracturing，the pores in the pore-vug cores decrease sharply and the reduced pores are mainly micropores and mesopores with a radius below 0.5 mm. The average pore radius greatly increases，while the most increased pore radii are in 0.5-0.8 mm. There is an upward trend in the pore volume，the throats，average throat radius，average throat length as well as total throat volume，and the proportion of fractures and vogs and the volume of connected pores and throats increase drastically. The experiments indicate that after recovery from stress，the flow capacity of the ultra-deep carbonate reservoir does not decrease but greatly increases，and fracturing mainly improves the connectivity of pores and throats by increasing the proportion of fractures in the pore-throat space.