Abstract: Xinli mining zone is the first hard rock mine in our country,which the deposit is under-sea.In view of the complicated mining technical condition of under-sea deposit,using the engineering analogy,and through numerical simulation tools of ANSYS,theoretical calculation and orthogonal experiment,the influence of different design parameters to the mining security,resource recovery and so on are researched,and the structural parameters of pillar in the mining process are optimized,as well as the sufficient basis for the mining method designs are provided in this paper.