By the detailed survey on the structure features of left bank resisting rock of Jinping-I hydropower, resisting rock chambers were classified with surrounding rock classification. 50% resisting rock chambers belong to Ⅲ2, about 36% belong to Ⅳ, and the rest belong to Ⅲ1 and Ⅴ. By the study on excavating destabilization, analysis was made on the stability-loosing mechanism and the deformation pattern. Weak-plane-controlling block gliding and collapsing were thought to be the main deformation pattern. According to the analysis on the chamber monitoring data, no evidence showed any abnormal; but deformation of F5, F42-9 faults and lamprophyre dyke were slowly occurred. The paper put forward the construction proposal.