The invention discloses a method for preparing manganese zinc ferrite nanoparticles, and belongs to the technical field of preparation of nano magnetic materials. Ethylenediamine tetraacetic acid (EDTA) is utilized for chelating manganese, zinc, iron and other metal ions into sol, through further evaporating and drying, dry gel containing a metal ion chelate is formed, and finally, the dry gel issubjected to heat treatment at different temperatures to obtain the manganese zinc ferrite nanoparticles of a pure phase structure. The preparation method is simple in process and convenient to operate, the pure-phase manganese zinc ferrite material can be obtained at the low heat treatment temperature of 300-500 DEG C, the production cost is reduced, and the defects of high energy consumption, complex processes and easy impurity phase generation of a traditional high-temperature solid-state sintering method are overcome. In addition, through appropriate parameter adjustment, the method also can be used for preparing other ferrite materials except manganese zinc ferrite and has broad application prospects in the field of nano magnetic material preparation.