Pot experiment on red soil(garden soil) contaminated by heavy metal in Guixi city,Jiangxi province was conducted.The results indicated that using lime to tune soil pH to lightly alkalescence could improve net photosynthesis significantly,increase soil microbe C (especially for cellulose-decomposing bacterium),reduce the available content of heavy metal and reduce the harm to plants,so it's the viable amended measurment under the condition in existence.