The derivatives of natural polymer chitin and chitosan：sodium salt of carboxymethyl-chitin and chitosan acetate，were examined as the protective polymers for the formation of the precious metal colloids．In the presence of carboxymethylchitin or chkosan acetate，stable me-tallic colloids of palladium，rhodium，ruthenium，platinum silver and gold were formed in a methanol-water solvent system．Particularly，TEM measurements illustrate that the narrowly dis-persed metallic colloids with fine particle size can be formed in the case of palladium，rhodium or ruthenium carboxymethylchitin or chitosan acetate systems．That is in carboxymethylchitin protective system，palladium sol is mostly dis

ributed in the range of 4.0—5.0 nm with an ave-rage diameter of 4.6 nm and rhodium sol or ruthenium sol is in 3.5—4.5 nm wkh an average diameter of 4.0 nm or in 3.0--3.5 nm with an average diameter of 3.2 nm， respectively；in chitosan acetate protective system，rhodium sol is in 4.0—5.0 am with an average diameter of 4.6 nm．Palladium，rhodium and platinum sols were tested as catalysts for the partial hydro-genation of 1，3-cyclooctadiene and showed quite a good activity as well as selectivity．