Abstract: The oil leak accidents induced by different causes occurred in more than 30 years in the Northeast oil pipeline networks have been analyzed. A viewpoint on Determination Leak Category based on Leak Accidents is put forward. In the leak accident analysis, on the basis of the trend curve of leak accident varied as the time, the pipeline service life has been classified as initial stage, former sub-stability stage, stability stage, post sub-stability stage and ageing stage. In the paper, the authors predict that in the future decade, the Northeast oil pipeline networks of China will enter into an accident frequently-occurring stage, especially due to the corrosion and external force factors.