The safety of fully mechanized mining face was affected by many factors, including man, machine, working environment, and geological condition. Chosen main influencing factors as evaluation indexes. And the unascertained measure of the factors was defined by using the unascertained model. The index weight and attribute weight of evaluation target were calculated by using attribute hierarchy model (AHM). And a comprehensive evaluation system was established based on the unascertained measure and AHM. Finally, the correction and adjustment of this model was identified by a case study.