In this work, the adsorption properties ofcrosslinked chitosan for Mo(VI) were studied. The adsorptionrate of Mo(VI) by CCTS was 97% at pH 3.0. Adsorptionbalance time, elution conditions, the effect of coexisting elements,and the adsorption mechanism were investigated. Anovel method of ultratrace Mo(VI) preconcentration withCCTS and determination by graphite furnace atomic absorptionspectrometry was found. The detection limit (3_, n_ 10) of the method was 0.040 _g L_1, and the relativestandard deviation was 2.98% at 1.00 _g L_1. The methodhas been applied to the determination of Mo(VI) in environmentalwater samples, with satisfactory results.