Abstract: Under the background of “double carbon target”, China has actively promoted the development of hydrogen-blended natural gas pipelines. This paper summarizes the research advances and challenges in the integrity assessment of hydrogen-blended natural gas pipelines at home and abroad. The main conclusions are as follows. (1) The conclusion of the existing metal material compatibility test is not clear, and it is urgent to formulate an international unified metal material hydrogen compatibility test standard. The degradation law of pipe and weld performance after hydrogen doping is not clear, and relevant tests need to be carried out systematically to reveal the hydrogen damage mechanism. (2) The sealing performance and mechanical properties of non-metallic sealing materials for natural gas pipelines in hydrogen environment are still unclear, and relevant tests are urgently needed to explore their performance laws. There is a lack of high-performance non-metallic hydrogen pipelines in engineering, and it is necessary to develop low-permeability and corrosion-resistant hydrogen pipelines. (3) The existing non-destructive testing technology has insufficient research on the applicability of hydrogen-blended natural gas pipelines. It is necessary to improve or develop non-destructive testing tools with higher precision to meet the requirements of defect detection accuracy under hydrogen-blended conditions. (4) The research on the applicability evaluation method of hydrogen-blended natural gas pipeline defects is still in its infancy. It is necessary to carry out the research on the microscopic damage constitutive of the pipe considering the hydrogen medium and stress state based on the abundant experimental data, and improve the applicability evaluation method of hydrogen-blended natural gas pipeline defects. This paper can provide reference for related research on safety assurance of hydrogen-blended natural gas pipelines.