Because of the underground mining, a large number of goaf are formed, the collapse accident is prone to happen, especially for the mines from underground mining changing into open-pit mining, there are hidden dangers to the safety production of the mining area. In view of this situation, this paper studies a filling well completion technology for multi-layer goaf to carry out support treatment. By means of this process, the amplitude of rock movement can be reduced to prevent the large area of ground pressure activities, so as to provide guarantee for the production and safety. Due to the different conditions of the specific location, morphological characteristics and size of the goaf in each mine, the treatment methods for goafs are not the same. According to the characteristics of Luanchuan molybdenum mine goaf, this paper introduces the study and test on filling well completion technology.