The present invention provides method for preparing a cross-linked ceramic-coated separator containing an ionic polymer, a ceramic-coated separator prepared by the method, and a lithium secondary battery using the same. According to preferred methods for preparing a cross-linked ceramic-coated separator, a coating material containing ceramic particles for improving thermal and mechanical characteristics, a functional inorganic compound for improving cycle characteristics and high rate characteristics of a battery, and an ionic polymer for bonding the ceramic particles and the functional inorganic compound on a porous membrane substrate is coated on the porous membrane substrate and subjected to chemical cross-linking.