There are significant impacts on the safty of tunnels because of porous materials.In order to avoid serious accidents of tunnels, Porous materials of carbonate rocks under the condition of low temperature and high pressure have been studied in the paper. Samples of local carbonate rocks have been collected from carbonate rock formation. Special machine was designed to simulate the condition of low temperature (10°C-20°C ) and high pressure (1-30Mpa) undergroud 4000M in jinping.Samples of local carbonate rocks have been tested in the machine. Spectrographs and scanners have been used to observed the change of porous materials of carbonate rocks.Results of the technological measurements show that the change of porous materials of carbonate rocks is affected by low temperature and high pressure.With the change of low temperature and high pressure, surface chemistry is affected throughout the surface of carbonate rocks. When the temperature of carbonate rocks exceed 15°C and pressure less than 18Mpa,there will be new compounds on the surface of carbonate rocks. These new compounds will change the porosity and thesaturated permeability of carbonate rocks.The change may led to serious accidents of tunnels.If we want to avoid these serious accidents,we must keep the temperature of carbonate rock formation less than 15°C and pressure exceed 18Mpa.