Effects of water-soluble products of rice straw,Chinese milk vetch and pig manure on precipitation and adsorption of Cu and Cd on a red soil and a fluvo-aquic soil were studied.Two opposite effects,pH^- raising effect and complexing effect,were observed.At same pH values,the water-soluble organic products depressed Cu and Cd precipitation and adsorption by forming soluble organic-metal complexes.Cu adsoprtion was more strongly inhibited than Cd adsorption because of the stronger complexation ability of copper.The adsorption isotherms showed that the water-soluble products enhanced Cu and Cd adsorption by raising pH values when the pH values were not adjusted.