Abstract: The pillarless sublevel caving is one of major mining methods in underground mine at home and abroad. As for the equipment constraint of rock drilling and blasting,the sublevel caving with small structural parameters has been applied for a long time processing with dynamite, and ore removal, which caused some problems such as serious ground pressure and low mining efficiency. In recent years, enlarging structural parameters is gradually used in pillarless sublevel caving, which improves both the mining stability and economic efficiency. Therefore, the analysis of underground pressure in pillarless sublevel caving favors the realistic safety, and the high effective mining. Three different structural parameters models (10 m×10 m, 15 m×15 m, 15 m×20 m) have been simulated. By adopting three-dimensional finite element method, and analysis has been done on the displacement and stress on the different processes of excavation and ore mining. The results are as follows: Firstly, compared 15 m×20 m with 10 m×10 m, the displacement of admission passage roof is reduced by 20.1% and the minor principal stress is also lowered by 18.8%. Secondly, the roof displacement and the stress in mining process is smaller than excavation process; the problems of underground pressure has been improved. Thirdly, the vertical displacement and principal stress is lowered with the increase of the structural parameters both in excavation and ore mining process. The results show the higher structural parameters possess better stability, and can improve the underground pressure. Therefore, using the large-spacing pillarless sublevel caving is safe and feasible

Key words: pillarless sublevel caving, structural parameter, finite element numerical simulation, stope mining stability