Regeneration cleaning process of combined filter element

The invention discloses a regeneration cleaning process of a combined filter element. The regeneration cleaning process comprises the following steps: performing pretreatment in a solution consistingof a dispersing agent, an emulsifying agent, a cosolvent and water; performing ultrasonic treatment or high-pressure water washing as transition treatment; performing conversion treatment in a conversion solution prepared from strongly basic sodium salt; performing ultrasonic treatment or high-pressure water washing as transition treatment; carrying out fine treatment in a solution consisting of achelating agent, a corrosion inhibitor, a surfactant and water; performing ultrasonic treatment or high-pressure water washing as transition treatment; performing post-treatment in an aqueous solution containing a passivator and a brightener; then, performing ultrasonic treatment or high-pressure water washing; and finally drying the filter element. Through the process, the filtering element is cleaned more thoroughly, th