Abstract: With the organic combination of Fuzzy sets, grey system theory and other mathematical methods,the paper proposes systematicaly a set of research methode for quantitive prediction and assessment of complexity of structures in coal mine, which concerns the optimun seeking of assessment indexes, the assessment examination in mined area, and the quatitive prediction and comprehensive assessment of unmined area. The set of methods has been successfully used in the prediction of structures in Jin huashan coal mine in Tun chuan mine district, and selected two blocks which have simple geological condition for mining. The suggestion has been accepted by mining department of the mine.