The large abandoned slag body of the cold rolling mill is located on the right bank of the outlet of the diversion channel of Jinsha Hydropower Station. The discharge of the diversion channel will cause backwash to it. In order to ensure the stability of the bank slope and protect the factories or mining enterprises on the top, it is necessary to analyze its stability, especially the stability changes during the discharge of the diversion channel. Based on the characteristics of the waste slag body, the overall stability analysis is carried out by using methods such as Jabu Method. According to the failure mode and degree of the bank slope caused by the channel discharge to the waste slag body, combined with the results of the model test of the flow bed, the flexible protection scheme of steel mesh and steel wire gabion protective structure is proposed innovatively.