The geological conditions of coal seam are evaluated quantitatively by using fuzzy method and from pointview of coal mining. According to the evaluation results, decision-making on mining techniques, mining programming and design, production management can be carried out effectively. The latest developments in China are introduced. The evaluation contents, the structure and index system of evaluation factors, the membership functions and weights of evaluation factor, evaluation model and reliability are stated in detail. The effective application of fuzzy evaluation in the prediction of coal face output is introduced emphatically. Fuzzy evaluation on geological conditions of coal seam is the basic work that ensures a mine run efficiently, safely and steadily.