The invention relates to a preparation method of a sugar-metal complex and an application thereof as an anti-caking agent for salt. The application is characterized in that sugar-metal complex powderor combined liquid of the sugar-metal complex powder is added into the salt, and is fully and uniformly mixed to be as the anti-caking agent for the salt. The sugar-metal complex is used as a supplementing agent, not only the matching stability is proper, but also the ligand sugar has various biological activities after the release of iron, is a beneficial component to the body, can be absorbed and utilized and is natural and nontoxic; the invention finds a new anti-salt-caking agent to open up a new road for developing the biological sugar-metal complex and also provide an important evidencefor research, development, application and promotion of the anti-caking agent.