Disclosed are a SA@CDs/g-C3N4 composite material, a method for preparing same, and an application of the same to aflatoxin removal, which belong to the technical field of organic materials. The method for preparing a SA@CDs/g-C3N4 composite material includes: adding a CDs/g-C3N4 compound into water, and uniformly dispersing same through ultrasonic treatment; adding sodium alginate, intensely stirring and fully mixing a mixture, and forming a pregel solution; transferring the fully mixed pregel solution into a mold, and freeze-drying the pregel solution to obtain sponge; and soaking the sponge in a CaCl2) solution for gel, performing washing with deionized water, performing freeze-drying, and obtaining the SA@CDs/g-C3N4 composite material. The SA@CDs/g-C3N4 composite material prepared according to the present disclosure can effectively remove residual aflatoxin in foods, and is wild in effect, environmentally-friendly and safe.