Advanced oxidation processes (AOPs) have been widely used in contaminants decomposition to reduce their harm. Especially, the singlet oxygen (¹O₂)-mediated AOPs have been considered a promising decontamination method due to their good ability to resist water matrix in actual wastewater treatment. However, there are still some doubts about the important role of ¹O₂ in wastewater treatment. Therefore, it is necessary to comprehensively summarize the characteristics, detection methods, and generation pathways of ¹O₂ based on the latest research. In this review, various characteristics of ¹O₂ are comprehensively summarized, including its molecular structure, orbital energy, lifetime in solvents, reaction characteristics and reaction pathways. Next, the generation pathways of ¹O₂ including catalytic ozonation, hydrogen peroxide, persulfate, periodate, photocatalysis, electrochemical, and peracetic acid activation systems are summarized. Additionally, ¹O₂ can be detected by various methods such as fluorescence probes, chemiluminescence probes, quenching tests, electron paramagnetic resonance, deuterium oxide experiments, and product analysis. The combination of multiple detection methods can improve accuracy of ¹O₂ detection. Finally, the existing deficiencies and improvements in mechanism exploration, detection means and practical application of ¹O₂ are also contained. It is expected that this review can provide new inspiration for subsequent research on ¹O₂ -mediated AOPs.