The invention provides a preparation method for an aerogel type sewage cleaning agent.The preparation method comprises the steps that firstly, furfural, water soluble phenol-formaldehyde resin, sea-foam stone powder, halloysite nanotubes, nano crystalline cellulose, polyvinylpyrrolidone and water are mixed, mixed liquid A is obtained, ammonium hydroxide is dropwise added into the mixed liquid A, and then sol A is obtained through a reaction; secondly, butyl titanate and absolute ethyl alcohol are mixed to obtain mixed liquid B, a hydrochloric acid solution, absolute ethyl alcohol and water are mixed to obtain mixed liquid C, the mixed liquid C is dropwise added into the mixed liquid B, and after a reaction, sol B is obtained; thirdly, the sol A, the sol B and phenoxy resin are mixed evenly to obtain mixed sol, solvent replacement is conducted after the mixed sol is aged, and mixed gel is obtained; fourthly, supercritical fluid is adopted to dry the mixed gel, and the aerogel type sewage cleaning agent is obtained.The aerogel type sewage cleaning agent prepared through the method is good in adsorption effect, high in adsorption capacity, short in cleaning time and high in efficiency, and the cleaning time is short.