Abstract: The present invention relates to a postsurgical adhesion barrier of carboxymethylchitosan, carboxymethylchitosan/carboxymethylcellulose cross-linked with multivalent ions and a method for preparation of the barrier. The method of preparation comprises: preparing a carboxymethxylchitosan polymer aqueous solution and carboxymethylcellulose polymer aqueous solution in purified water respectively, applying the carboxymethxylchitosan solution, or a mixed solution of carboxymethxylchitosan and carboxymethylcellulose with certain weight ratio on a smooth plate, drying the plate with the applied polymer aqueous solution to obtain a film thereon, socking the dried film on the plate in a aqueous solution of cross-linking agent selected from Ca++ ion, Fe+++ ion, a mixture of Ca++ and Fe+++, or a mixture of Ca++ and Al+++ to complete cross-linking reaction, and drying and detaching the cross-linked film. The obtained postsurgical adhesion barrier is biocompatible and bioresorbable.