Abstract: There are multi-level decoupling detachment phenomenon existing inthe lithosphere.The listric normal faults formed by the extention processeson the mine field’s edge crossed on the deep-level detachment structure plane,but the shallow-level detachment structures were the result of thegravity gliding after the earth crust extended.These multi-level detachment structures was the most important factor which formed the Xinwen minefield’s tectornic framework.