Abstract: In order to study the stability of the goaf in a mine，the MAPTEK SR3 three-dimensional laser scanner is used to detect the goaf comprehensively and accurately，and the three-dimensional solid model of the goaf is established. On the basis of engineering geological investigation and indoor rock me⁃ chanics test in goaf，the stability coefficient and hydraulic radius of goaf are calculated by Mathews graph⁃ ic method，and the stress，displacement，plastic zone size and distribution of surrounding rock and pillar in goaf are analyzed by numerical simulation method. The results show that the hydraulic radius values of each partition in the goaf are all within the stable area. The vertical displacement and horizontal displace⁃ ment values of surrounding rock and pillar in the goaf are at a low level. The stress concentration area and plastic failure area are mainly distributed in the surface rock mass of roof and pillar，which may lead to roof and pillar falling or local dangerous rock mass collapse，but it has little effect on the overall stability of roof and pillar. The stability of the mined-out area is good，and the possibility of pillar instability and the overall collapse of the mined-out area is low. The research results provide technical support for mine safety production management and goaf management design.

Key words: goaf, laser scanning, Mathews graphic method, numerical simulation