The humidity control composite paperboard with excellent humidity control performance was prepared, comprising sodium chloride, anhydrous potassium carbonate, diatomite, pyrrolidone carboxylic acid-Na, carboxymethyl cellulose and self-made humidity control material. The moisture absorption and desorption rate of the sample are about 0.6231 (g/7h•g-1) and 0.5852 (g/7h•g-1), respectively. The equilibrium humidity fluctuates from 52% to 56% and moisture capacity is 31 %. Moreover, it can reach to the equilibrium levels within 60 minutes. Above all, it shows outstanding humidity control properties, meeting the requirement of micro-environment particularly for something sensitive to humidity such as cultural relic.