The sliding zone made up of fault F42-9 and lamprophyre controls the stability of left cable-machine slope and arch dam abutment slope at Jinping First Stage Hydropower Station. The elastoplastic mechanism about reinforcement slope during excavation is simulated based on the occurred texture planes parallel to fault F42-9. The analytical results show that the designed reinforcement scheme can not ensure slope stability because of the sharply decreasing with rock mass behavior when the texture planes parallel to fault F42-9 are concerned. For sake of slope stability

it is proposed to design stronger reinforcement measures timely based on the exposing geological data during cable-machine slope and arch dam abutment slope excavation.