The invention discloses an attapulgite-clay-based composite fluorescent material, and a preparation method and an application thereof. The attapulgite-clay-based composite fluorescent material is prepared by the following steps: adopting amino-modified attapulgite clay as a substrate material, loading perylene-diimide type organic fluorescent dye on the surface, utilizing large specific surface area, high heat stability and excellent organic-group aging-resistant protective capability of attapulgite clay, adopting the amino-modified attapulgite clay as a substrate, and enabling amino groups to react with perylenetetracarboxydianhydride derivatives. The attapulgite-clay-based composite fluorescent material disclosed by the invention has the advantages that the phenomenon of easy auto-agglutination of perylene-diimide type compounds is improved to a certain extent, the fluorescence intensity is obviously enhanced, multiple organic pollutants can be detected and fast detection of low-concentration organic pollutants is realized.