The invention discloses a composite cathode of a chromium-pollution-resistant solid oxide fuel battery and a preparation method thereof. The composite cathode comprises an active layer and a collector layer. The active layer is arranged on an electrolyte layer, and the active layer is made of LNF-doped CeO2; and the collector layer is arranged on the active layer and made of LNF. The preparation method comprises the following steps of step1. adhering the pulp which is formed by the preparation material of the active layer onto the electrolyte layer to be dried, and preparing an active layer blank body; step 2. adhering the pulp which is formed by the preparation material of the collector layer onto the active layer blank body, and drying the pulp to obtain the collector layer blank body, and compounding the prepared active layer and the prepared collector layer into a cathode blank body; and step 3. sintering the composite cathode blank body. The composite cathode has excellent electrochemical catalytic performance and chromium pollution resistance; the preparation method has the advantages of simplicity in process, short preparation period and low cost, and the chromium-pollution-resistant solid oxide fuel battery is applicable to the industrialized application.