Abstract: In order to solve the safety and high efficiency mining problems of 7 m mining height fully-mechanized working face in Shendong Mining Area, the field m easurement, theoretical analysis and physical simulation methods were used to study the 19 ultra large mining height working faces of rock pressure law and key techn ology. The research results showed that compared with ordinary working face the strata behavior of the ultra large mining height working face more intense; because of ultra large mining height working face increased obviously, the No. 1 sub key strata entered the caving zone easily, it was difficult to form the structure of voussoir bea m, and the cantilever beam structure of periodic breaking the pressure to work, the formation period, the duration and distance of support roof to the key strata structur e of voussoir beam pressure persistence length was larger; and with the increase of buried depth, high key strata breaking was also gradually increasing influence on ul tra large mining height working face, synchronous breaking it would pass off overlying strata load more key layer, there by increasing the working face. Aiming at ultra I arge mining height working face of strata behavior characteristics and special rock breaking law.The author established a method to determine the reasonable working「 esistance of support, development of mining equipment of ultra large mining height working face, the support technology of large cross section tunnel, forced caving tec hnology and rapid through technology during terminal mining technology to achieve safe and efficient mining of ultra large height working face.