Abstract: The stability characteristics of the main seam roof in Longgu Coalfield were analyzed.And the factors influencing the seam stability were the sedimentary characteristics,tectonic characteristics,mechanical property,etc.The seam roof had different kinds according to different classification standards.Summarizing all the factors,the seam roof stability characteristics were analyzed by the method of artificial neutral network(ANN).The seam roof stability was analyzed from the following five grades: most stability,more stability,middle stability,less instability and instability.The zones of the most stability were of thick coarse sandstones with few structures and extremely high strength.The zones of more stability were of medium-bedded fine sand and silt with a few structures and intermittent and high strength.The zones of middle stability were of silt and mudstone with many structures of partly cutting through and medium strength.The zones of less instability were of mudstone and seam with large quantity of continuous structures and lower strength.The zones of instability were of mudstone and seam with large quantity of continuous structures and the lowest strength.