Abstract: The treatment of metal mined underground goaf has always been one of the problems that mining needs to overcome.To discuss the evaluation of the stability of the goaf,from the perspective of system engineering,this paper applies the basic principle of fuzzy mathematics to construct a twolevel fuzzy evaluation model for the stability evaluation of a goaf.The four logical partition function method is used to determine the membership function,and the weight distribution matrix is established based on the analytic hierarchy process.And the results of the risk assessment of the mining goaf are obtained.The results showed that the geological structure,high span ratio,rock mass structure,maximum exposed area are very important to the stability of the goaf.Factors such as the adjacent goaf,the inclination of the ore body,and the disturbance of the mining have certain influence on the stability of the goaf,but it is not the main factor.The research results basically reflect the actual situation of the mine goaf at present,and provide a reference for the mine goaf governance.

Key words: four logical partitions,goaf area,stability,fuzzy evaluation