Abstract: Hydrogen, as a clean energy carrier with high energy density and zero carbon emissions from combustion products, has an irreplaceable central position in the future energy system. In the strategic context of global energy structure transformation and dual carbon goals, the development of sustainable renewable energy hydrogen production technology is a key path to cope with the energy crisis and climate change. However, current mainstream hydrogen production processes （such as steam methane reforming） are highly dependent on fossil fuels, accompanied by significant carbon dioxide emissions, which restrict their environmental benefits. Therefore, green hydrogen preparation technologies driven by renewable energy sources （such as green electrical energy and light energy） have become a research focus. Three types of renewable energy hydrogen production technologies are systematically reviewed from the perspectives of principles, challenges, and scale-up potentials: ①As the most mature “green hydrogen” production technology currently available, water electrolysis for hydrogen production features both rapid start-stop capability and flexible load response. It is compatible with hydrogen production using renewable energy sources with strong volatility, such as wind power and photovoltaic power, and can effectively absorb and store renewable energy. Water electrolysis for hydrogen production encompasses alkaline water electrolyzers, proton exchange membrane electrolyzers, anion exchange membrane electrolyzers, and solid oxide electrolyzers, with their respective technical characteristics. The core bottleneck is the cost problem caused by high power consumption, coupling with renewable energy is regarded as a core pathway to reduce electricity costs. With the continuous decrease in the costs of renewable energy power generation and electrolyzers, the cost of green hydrogen is expected to achieve parity. ②Photocatalytic decomposition of water to produce hydrogen can be directly driven by solar energy to decompose water, which is theoretically advantageous. It faces the challenge of low conversion efficiency of solar to hydrogen, so the development of high-efficiency and stable photocatalysts is the key to the breakthrough. ③Photoelectricity chemical decomposition of water to hydrogen combines the advantages of photochemical decomposition and electrochemical decomposition, with great potential. However, the conversion efficiency still needs to be greatly improved, the development of larege-scale, efficient, stable and low-cost photoelectrode materials is the core task of the current research. In addition, the large-scale application of the three hydrogen production technologies plays an important role in energy reform, and then elaborates on the large-scale pathways of these three hydrogen production technologies. Finally, the direction of technological innovation is discussed from the three dimensions of efficient activation and utilization of raw materials （water）, optimal control of process energy consumption, and enhancement of output per unit of energy consumption, and the focus of future research is also looked forward to. Currently, water splitting for hydrogen production technology imposes relatively high requirements on the purity of feedwater, necessitating pre-treatment of water quality prior to hydrogen production, which incurs additional cost input. Furthermore, the global shortage of freshwater resources and uneven geographical distribution further restrict the large-scale application of hydrogen production technology based on pure water. Distributed hydrogen production technology using atmospheric water harvesting and direct seawater electrolysis for hydrogen production can fundamentally address this issue. On the other hand, reducing the cost of hydrogen production and improving the energy utilization efficiency of hydrogen production systems are also of crucial importance. These discussions aim to provide references for promoting the development of efficient, economical, and sustainable “green hydrogen” technology.