For the on-line inspection of LNG pipelines, this paper adopts infrared thermography, pulsed eddy current, digital radiography (DR), electromagnetic ultrasonic thickening and other inspection technologies to carry out on-site validation tests on LNG pipelines and analyzes the main problems existing in the on-site inspection of each technology and puts forward relevant suggestions. Problems in the current regulations and standards for on-line inspection of LNG pipelines are discussed, and suggestions are made to formulate and improve regulations and standards related to on-line inspection of LNG pipelines. For the applicability of on-line inspection technology for LNG pipelines, tests on inspection technologies such as pulsed eddy current and digital radiography were carried out by simulating on-line working conditions. Infrared thermal imaging, pulsed eddy current, digital radiography (DR), electromagnetic ultrasonic thickness measurement and other inspection technologies are used to verify the nondestructive testing technology on-site for LNG pipelines in operation, and the results show the feasibility of on-line inspection of LNG pipelines. The current inspection standards for LNG pipelines are also analyzed, and several proposals are put forward to modify and improve the regulations and standards for on-line inspection of LNG pipelines.