Abstract: Based on the other reseachers' work, the Gumbel Ⅰ distribution of mining tremors' extreme magnitude is derivated.The determination method of the distribution parameters is also developed. After bri-efly introducing the tectonic structure and physical background of mining tremors in Laohutai coal mine, the magnitade extreme distribution is applied to the practice of probabilistic prediction of monthly largest magni-tudes at the Laohutai coal mine.The result shows that the predicted probability distribution of monthly largest magnitudes consists well with the distribution of practical record of monthly largest magnitudes.