Abstract: According to the results of systematical engineering geological surveys, based on the rock mechanical experiment of specimens from-430 m level to-568 m level, the Q system which is well applicable to high geostress conditions and the RMR method were applied to rock engineering classification. The relation of rockbursts to the values of RMR and RQD was analyzed. It is known that there is the probability of rockbursts below-500 m level in Chengchao Iron Mine. The influence of high geostress environment on rockburst preparation was discussed by studying geostress distribution laws. Finally, the distribution state of energy in surrounding rockmass during deep mining excavation was studied by 3D FEM numerical analysis, and it is inferred that the critical depth of rockbursts is-500 m. On the base of simulation results, the in-situ stress strengthens significantly at-500 m level due to the impact of upper mining activities, higher than at-533 m level. Below-533m level, the maximum value of rockmass energy also progressively increase with the incremental vertical depth.