o-Nitrobenzaldehyde (ONBA) is an important organic synthesis intermediate, which is widely used in medicine, dyes, pesticides and other fields. The development of its green and efficient synthesis process is of great value in the field of selective oxidation research and chemical production industry. In this paper, the research progress of the synthesis process of ONBA is reviewed. The homogeneous and the heterogeneous catalyst reaction system are analyzed, and the representative and innovative research results in each system are introduced. Homogeneous catalyst systems include liquid-phase chemical oxidation and electrochemical oxidation methods that are still in the research stage. The heterogeneous system covers green synthesis methods such as thermal catalysis, photocatalysis and biomimetic catalysis. This paper also points out the problems existing in the current research, such as low catalyst performance and stability, insufficient research on reaction mechanism, and the influence of o-nitro electron-withdrawing group on substrate activity. In the future, it is necessary to carry out in-depth research in this field around the development of green oxidants, exploration of reaction mechanism, and precise design of catalysts, so as to promote the green, efficient and sustainable development of ONBA synthesis process.