Abstract: In new power systems, high penetration of renewable energy may lead to significant curtailment due to insufficient energy storage and consumption measures, and fluctuation and intermittence of wind/solar power also contribute to the grid's instability. The electricity-hydrogen collaborative technology with water electrolysis technology as its core can assist in the large-scale consumption of excess wind/solar energy, improving energy efficiency, and contribute to regulate the power grid peak, voltage, and frequency. In this review, we compare and analyze the principles and technical characteristics, performance indexes, and processes of industrialization of various types of water electrolysis technology for hydrogen production. Then, based on the current situation of electric hydrogen production and hydrogen energy storage, we summarize the opportunities and challenges of the new power system with the participation of electro-hydrogen synergy technology. Finally, we discuss the feasibility and research progress of water electrolysis technology as a method of supporting the power grid based on renewable energy, as well as the potential for further exploration of the electro-hydrogen synergy technology for improving power grid support capabilities.