Research conclusions:(1)For the small一sized mined一out region，the survey should be conducted from the big area to small area for knowing the overall condition of the mined一out region in macroscopic view first and then studing the area where has impact on the railway construction.(2)For the survey，first of all，the geological survey should be conducted，then the geophysical prospecting should be conducted and finally the exploration drilling should be conducted for verification， supplement and combination each other.(3)The key points of the survey should be made clear and appropriate method for the stability assessment should be chosen according to the different types of the mined一out region and the engineering features.(4)With the roof collapse blocking up method and the manual method，the checking calculation was made for the stability of the mined一out region. From the calculation result，it was concluded it was unnecessary to treat the mined一out region of Shangzhichang Mine.