As the regulations for the upgrading and transformation of wastewater treatment plants have become increasingly stringent, the process flow of wastewater treatment has gradually lengthened and become more complex. Addressing how to intelligently monitor operational conditions of process equipment and enhance fault management has emerged as a hot research topic due to the significant safety incidents and environmental pollution events that faults in wastewater treatment systems can cause. This paper starts by analyzing the characteristics of wastewater treatment process flows and the main types of faults. It comprehensively reviews the latest achievements and progress in fault detection and diagnosis in wastewater treatment processes both domestically and internationally. It summarizes three types of fault detection and diagnostic methods: model?based, domain experience?based, and data?driven approaches. The paper evaluates the current applications, strengths, and weaknesses of these wastewater treatment process fault detection and intelligent diagnostic methods, identifies existing problems, and anticipates future research directions in the technology of fault detection and intelligent diagnosis for wastewater treatment processes.