Abstract: According to scheduled outages of East China Power Grid, The task of 500 kV transformer fire-fighting rehabilitation needs to be finished within 48 hours. Currently, however, 50.17 hours was consumed in the first plan to perform and finish the task of fire-fighting renovation, and the time requirement was not satisfied.The key of problem and solutions was searched by QC group, then, a goal that the renovation of 500 kV Substation was limited into 39 hours.