Abstract: The high-voltage cables laid underground have strong concealment properties. If the pipeline location information is distorted and the ground identification is fuzzy,it will bring great difficulties to the subsequent equipment operation and maintenance and safety control. This paper introd uces an external force damage event of 110kV high-voltage cable caused by the pile punching of rotary excavator. Through the analysis and fault search of the event,it is concluded that the cause of the event is that the cable pipeline position is not clear and the ground identification is uncertain,resulting in the inability to effectively implement the material prevention device and set up safety signs; The poor connection between the relocation of cables and pipelines and the construction progress of the project leads to the poor extension of safety control measures. Formulate rectification measures according to the lessons learned from the incident to avoid the recurrence of similar accidents.