Abstract: The physical and mathematical model is built for the tubular diffusion and infiltration diffusion leaking process of the buried gas pipeline in both windy and windless weathers. The mesh of the model is partitioned using Gambit software while the numerical simulation is conducted using Fluent, a software, to compute fluid. The diffusion region and safe avoidance region of the two kinds of leaking process at different time and also the effect of soil permeability on the leakage and diffusion region and concentration distribution of natural gas are studied. The results show that the leakage of gas in windy weather has a larger influence on the ground diffusion. In addition, when the wind speed reaches a certain degree, safe region only exists in the windward direction of the leakage point. The residual velocity of the leaking gas after permeating the soil determines the diffusion height, range and forms of gas flow. Compared with the case that gas passes through the low permeable soil, the gas passing through the high permeable soil has a larger diffusion region in the air and a higher diffusion height. However, the diffusion ranges of the two cases are almost the same in the long run.