Abstract: In order to study the influence characteristics of leakage and diffusion of medium and high pressure gas pipelines in cities and towns near high-rise buildings, considering the wind acceleration effect caused by the gap between high-rise buildings and the influence of different leakage positions on gas diffusion, Fluent is used to numerically simulate the environmental wind field and gas leakage and diffusion. The results show that: For urban high-rise buildings, the diffusion direction and range of gas can be predicted by judging the steady-state wind field; The accelerating wind speed near the ground has little effect on the deviation of leakage jet, and the diffusion of gas presents a columnar distribution between buildings; The methane leakage on the windward side is lifted at the top of the windward side of the building, and the leakage on the leeward side tends to diffuse to the side without the building, and finally presents as a gas cloud close to the building and the ground; The smaller the distance between the leakage hole and the building, the greater the harmful area of methane attached to the building. The influence of building height should be considered when designing the distance between the gas pipeline and the building;The acceleration ratio is introduced to quantitatively characterize the acceleration effect between high-rise buildings, and the three-dimensional distribution of acceleration ratio between high-rise buildings is proposed. The research can provide a theoretical basis for the prediction of urban gas pipeline leakage accidents and the emergency evacuation of personnel.

Key words: gas pipeline, high-rise building, leakage and diffusion, acceleration effect, safe distance