The invention relates to a zinc ferrite composite oxide fine desulfurizer and a preparation method thereof. The zinc ferrite composite oxide fine desulfurizer combines the advantages of traditional conventional desulfurizer iron oxide and the fine desulfurizer zinc oxide, and an atomic layer deposition method is used for synthesizing the composite oxide zinc ferrite fine desulfurizer having the advantages of complete crystal form, high crystallization degree, and uniform dispersion. The zinc ferrite composite oxide fine desulfurizer has the advantages of high desulphurization precision and high sulfur capacity, and is the fine desulfurizer having large industrial potential.