Abstract: The process of repair and emergency response of natural gas pipeline are framed based on the principle that mitigating pipeline risk should start with two aspects-failure probability and failure consequence. Main steps involved in this process are analyzed, including threat origins, threat types, threat degree, repair measures or measures taken for emergency response and work in late stage, etc.. There are two types of threat-potential threats and accidents, and eight types of pipeline threat origins including external corrosion, internal corrosion, stress corrosion crack, manufacturing related defects, mechanical damage, construction related defects, outside force and geotechnical threats. It is pointed out that attention must be paid to the basic concept of oil/gas pipelines'repair and emergency response and in emergency preparation.