Conducting risk assessments for hydrogen energy systems and facilities is essential for preventing hydrogen accidents and ensuring the safe use of hydrogen energy. With the advancement of commercial applications of hydrogen energy, diversified hydrogen energy application scenarios have put higher demands on risk assessment technologies. This paper summarized the fundamental theories and methods of both qualitative and quantitative risk assessments and reviewed the current development status and main application scenarios of existing risk assessment technologies in the hydrogen energy industry. Emerging risk assessment technologies, such as dynamic Bayesian networks and artificial neural networks, were introduced as well. On this basis, this paper highlighted current challenges in hydrogen safety data, dynamic quantitative risk assessment, risk assessment procedures and acceptable standards, and simulation and assessment tools. Finally, four recommendations were proposed for the future development of hydrogen risk assessment technologies.