Abstract: Taking the deep & large-sized orebody of Sishanling iron mine as an example, the after- mining block caving filling method has been employed to obtain the optimal structural parameters. With the help of orthogonal experiment, 16 simulation schemes have been designed. Using the FLAC3D to conduct calculation, the interrelated correspondence has been achieved between 5 factors in stope structural parameters and 8 indexes for stop stability. Adopting the unsupervised and competitive study, 16 groups of scheme data have been applied to SOM model for data inputting. Therefore, based on SOM model, the analysis of the prediction for expansion schemes, reversal analysis for structural parameters and the stability-related factors have been done. The results have shown that the length of stope serves as the most influential factor to stability, then the height of stope less influential, while the other factors may not arouse much consideration. The optimal stope parameters for the deep and large-sized orebody in Sishanling iron ore are as follows：100 m level height, 50 m stope length, 15 m room and pillar width and using tailings for backfilling.

Key words: SOM technique；deep &, large-sized orebody；optimization of structural parameters； numerical simulation