The invention belongs to the field of material science and engineering, and discloses a metal organic framework magnetic composite material and a preparation method and application thereof. The preparation method comprises the following steps that 1, carboxyl functionalization is carried out on Fe3O4 particles, and then the carboxyl functionalized Fe3O4 particles are washed and activated; 2, the carboxyl functionalized Fe3O4 particles are added into a reaction solvent and dispersed uniformly through ultrasonic treatment, and a mixed solution A is obtained; an organic ligand is added into the reaction solvent and stirred to be completely dissolved, then the mixed solution A is added and uniformly stirred and mixed, then soluble aluminum salt and an auxiliary agent are added, stirred and uniformly mixed to form a mixed solution B, then a heating reaction is carried out, and a metal organic framework magnetic composite material primary product is obtained after the reaction is completed;3, the primary product is washed and then heated and activated to obtain the composite material. Compared with a single MOF material and the Fe3O4 particles, the composite material has the advantagesof being higher in adsorption capacity and greatly shortening adsorption time.