Abstract: Taking the leakage of stored liquid ammonia in a factory as the research object, the SLAB model was applied to simulate the environmental emergency rescue system for the leakage accident. The consequences in adverse environment conditions (such as low wind speed in the winter) following the accident of liquid ammonia leakage were predicated by use of the SLAB model, including the concentration of immediate threat to life and health (IDLH), the permissible exposure concentration in 15 minutes, the diffusion range of the harmful substances' maximum permissible concentration in the residential atmosphere. The predicted results of the model clearly reflected the dangerous areas into which ammonia could possibly diffuse after the leakage accident. Specifically, within the areas of 0-435.8, 435.8-797.1 and 797.1-1 031.6 meters downwind from the leakage source, the ammonia ground concentrations respectively exceed IDLH, the maximum permissible concentration of ammonia in the workplace and the maximum permissible concentration of the harmful substances in the residential atmosphere, when the leakage time reaches 10 minutes. The rescue commanders can quickly comprehend the accident consequences according to the prediction, and make correct rescue programme in time.