Abstract: In order to study the mine pressure behavior law of the fully mechanized coal mining face, based on the site measurements, the numerical simulation me thod was applied to the simulation study on the distribution law of the plastic failure zone at the front of the coal mining wall under the different mining heights and differ ent coal mining face lengths.The results showed that with the mining height and the coal mining face length increased, the plastic failure scope at the front of the coal m ining wall would be getting larger and larger.When the length of the coal mining face was 220 m, with the mining height increased, the plastic failure scope at the front 0 f the coal mining wall would be in a potential of expansion.When the mining height was 4.5 m, with the length of the coal mining face increased, the plastic failure scope at the front of the coal mining wall also would be in a potential of expansion.