Abstract: The occurrence of orebody is superposition in the vertical direction, each other between the close, even links in the same place in Tongken ore area. Nowadays, ore area has formed the complex interplay of exploitation pattern due to the multi-layered orebody mining repetition and working in the multi-center-sections at the same time. After more than 30 years large-scale mining, ore area has accumulated millions of cubic meters of mined-out area, lead to the mining of technical difficulty and ground pressure control is extremely complex. Base on research of the rock mass engineering geology condition to mine, this paper has proposed the reasonable structural parameter to 92 ore body stope by carrying on computation to the stability of pillar and intermediate pillar, making use of nuclear area theory of strength and the Bieniawski intensity formula, and analysis the safety thickness of top pillar by using elastic-mechanical theory of small distortion thin steel plate, and the conclusions have also supplied technical evidence for the safety controlling the orebody 92 mining.