Abstract: An in-line overhaul program for Huatugou——Golmud oil pipeline is put forward due to serious corrosion in the pipeline in recent years. The in-line overhaul principle is to decrease leakage loss, eliminate environment pollution and save cost. The in-line overhaul program has been successfully implemented and helpful results have been obtained. In the paper, the site test and in-line overhaul process are introduced.