Abstract: With the development of China's oil and gas pipeline industry in recent years, the current defects assessment technology of oil and gas pipelines in China has not adapted itself to the needs of development of pipeline industry to a great extent. Under these circumstances, an urgent task to be done is to establish a defects assessment standard applying to the pipeline industry. In the article, the defects assessment methods and related standards and codes of oil and gas pipeline of foreign countries are introduced, and the latest assessment methods nowadays are discussed, which can provide a scientific fundament to establish the defects assessment standards for China's oil and gas pipelines.