Abstract: The engineering geological problems occurred in the land overlying worked-out area of coal mine were introduced． The methods of field investigation and experimental simulation of the engineering geological conditions of mined-out area were put forw ard． With the properties of reactivation of mined-out area， the suitability of the land overlying mined-out area to construction was analysed． Effective measures to strengthen the foundation soil and to protect the buildings from subsidence were given．