///In the case of Zaomu highway under goaf, using high density resistivity imaging method, high resolution seismic sonar and acoustic detection method to determine its location, then exploration and drilling result contrast analysis to determine goaf. The results show that the north and south sides of expressway central axis 50 m range, the detection area K3+580～ K3+830 section, a depth of 75～90 m range goof is widely distributed. According to the corresponding relation of the mining area and the caving zone, the authors can be infer the goaf space at heights of 3 to 8 meters. On the survey of mined-out area location and its characteristics, this paper puts forward the corresponding treatment measures.