The invention provides a cationic dye printing-dyeing wastewater treatment process, which belongs to the technical field of wastewater treatment. The treatment process uses a foam separation technique to treat cationic dye printing-dyeing wastewater, and concretely comprises the following: step 1, cationic dye printing-dyeing wastewater is collected and detected; step 2, the cationic dye printing-dyeing wastewater is pretreated; step 3, foam separation cyclic decolorization is carried out, which comprises a step of discoloring four times, wherein a device is a bubbling tower with the diameterof 32 mm; the decolorization needs sodium dodecyl benzene sulfonate as anionic surfactant every time; the cationic dye printing-dyeing wastewater after treatment meets the GB8978-1996 secondary discharge standard every time and is directly discharged; and a cationic dye crude product obtained by filtering anti-foam liquid is applied to a printing-dyeing procedure again; and step 4, evaporation and crystallization are carried out, and the collected cationic dye crude product is applied to the printing-dyeing procedure. The process has the advantages that the process can realize the industrial production of cationic dye printing-dyeing wastewater treatment, is convenient to operate and low in cost, and can greatly reduce secondary pollution.