In order to ensure the normal safety production and economic benefits of the mine, taking the complex goaf of an polymetallic mine in Hongling as an example, the stability of the goaf is studied aiming at the leaving number of goafs. Based on the field monitoring data, the stability of the barrier pillar, roof and the surrounding rock mass of the upper and lower wall are studied by the numerical simulation and the method of K. B. Lubeneyita formula. The rusults are compared with the actual situation on site. The results show that a comprehensive evaluation on the stability of the goaf is studied combining with the field investigation results, numerical simulation method and the empirical formula analysis method. The stability of the complex goaf and the potential failure area are also obtained comprehensively. The engineering practice is directed more effectively. Moreover, the research results has significant guidance value for the safe mining in the next step.