Some experiments on adjusting density of hard clam(Meretrix meretrix) in pond culture were carried out on the basis of the relationship between growth and density.According to the density dependent equation,transporting of clam from one pond to others for sparse culture was applied when the clam grows.The result showed that the pond with the higher density(8 840 ind/m~2 and 680 g/m~2)of hard clam had higher gross and net production,total output value,net profit and the ratio of output to input than the ponds with lower density;and that in the pond with density 1 253 ind/m~2(1 724 g/m~2)was higher than the others with low density in the mode of sparse cultured density; but the average shell length,height,width,size and weight of the hard clams in the pond with lower density were better than those with higher clam density.This study showed that control of the hard clam density in cultured ponds should be a measure to raise the production,quality and value of products.