Abstract: The effects of different amounts of copper adding to the lateritic paddy soil in Zhangjiang area of Guangdong Province on the growth and residue of rice and peanut are studied by pot experiment. The result indicates that the soil developed from basalt containing less than 200ppm Cu has beneficial rather than harmful effect on the growth of rice and peanut. The correlation between the concentration of added copper and its residue is significant in peanut, but not in rice. It is suggested that the critical concentration of copper in lateritic paddy soil is 277ppm.