Abstract: Hydrogen is a highly efficient green chemical. It is widely used as a feedstock for ammonia synthesis, petroleum catalytic hydrogenation, and methanol synthesis. As a green energy source, hydrogen has high combustion heat value, clean combustion products, and also act as gas source for anode of fuel cell. Hydrogen plays a pivotal role in human society. Natural gas is considered as the best raw material for hydrogen production, whose hydrogen production paths include partial oxidation,steam reforming, catalytic cracking, adiabatic conversion, dry reforming with carbon dioxide, and thermal reforming. Methane steam reforming is an efficient and economical method for hydrogen production and has been utilized on an industrialscale, which covers about half of the world's hydrogen production. However, as to the current process, challenges still exhist, such as reducing production costs, reducing carbon deposits, understanding the reaction mechanism, reducing heat transfer consumption, and reducing reaction temperature. Especially since the rise of fuel cell technology, the purity of H₂ is demanding, and the CO content in methane steam reforming gas must be as low as 10 ppm or less to avoid poisoning of fuel cell Pt electrode, which puts new requirements on the field of hydrogen production from methane steam reforming. Direct dehydrogenation of methane by catalytic cracking can directly decompose methane into solid carbon and hydrogen. The process is simple and high-purity hydrogen can be obtained. This process consumes less energy and has no pollution to the environment. It is the most promising high-purity hydrogen preparation process. Methane can also be used directly as a hydrogen source for coal-gas co-transformation or even oil-gas co-refining. This paper briefly introduces the background of hydrogen production from methane steam reforming, direct dehydrogenation of methane through catalytic cracking, summarizes the papers of international mainstream journals from January 20 to March 2019, and the international frontiers and development trends, and points out the key issues. This paper also introduces the research status and research characteristics in China and the status of the research team, points out the "strangulation" problem in China, and suggests the research fields and directions for key development in the future. By the way, the concept of coal-methane co-transformation and the idea of oil-methane co-refining are briefly introduced. It should be noted that due to the rather vast of the research fields, this modest review is not intended to be comprehensive.

Key words: methane, reforming, pyrolysis, hydrogen production, combined coal gasification and methane reforming, oil and methane co-refining