A catalytic cracking fume desulfuration wastewater treatment process is characterized in that wastewater is discharged to a slurry pool and is mixed with a flocculating agent, a stirrer is used for stirring the wastewater and the flocculating agent, the wastewater and the flocculating agent are mixed evenly, the wastewater after being mixed is discharged to an expansion tube type filter and is subjected to the coagulation reaction at the lower end of the expansion tube type filter, small particulate matters in the wastewater are flocculated, large flocculating bodies are formed, the solid-liquid separation is achieved through the filtration of a filtering film, thick slag and supernatant fluid are obtained, the supernatant fluid is discharged to an oxidation tank further, the thick slag is subjected to back washing and enters a subsequent filtering box, the thick slag is concentrated and dewatered in the filtering box, mud cakes which are concentrated are transported outwards, the water of dehydration returns to the slurry pool again, is mixed with the wastewater and is processed again, the false chemical oxygen demand (COD) which contains sulfite and bisulfite is oxidized and removed by the supernatant fluid in the oxidation tank, and the sewage which meets standards is discharged. Compared with the prior art, the process has the advantages that the area occupied by devices is small, the operation cost is low, the solid and the liquid can be separated completely, the working environment of workers is good, device parameters can be set in accordance with parameters of different materials, and the application is wide.