The effects of density on the growth of individual plant and per unit area and on the dry matter yield were studied with an ecological point of view in Red clover sward. 1. Different individual density caused no differences in plant height and length. 2. Comparing with the first period, the change in tiller number showed the most remarkable difference, but since the recovering metaphase the yield increase was decreased due to degenerating according to increasing of LAI. 3. The increase in leaves was rapid depending upon high density. The leaf number was followed as 600-D, 400-D, 200-D, 100-D in order. There is however, no agreement between leaf area index and dry matter weight. 4. The dry mater yield, 339.3g/㎡ yield with a 100-D was about one-half 644.8g/㎡ yield with a 400-D, but there is no difference between densities over a 200-D. 5. The increase in LAI was in direct production to leaf weight and dry matter weight, but there showed difference between LAI and leaf number. 6. The effects of an individual density on dry matter yield were studied utilizing LAI, CGR, NAR formulars depending upon each different density. The results were as follows. The yields in regenerating first stage and much density were large and high. The results when utilizing period of brasses is shorter, we should use neigh density conditions, and when grasses is longer, we should use low density condition. 7. The results of this study indicate that individual density condition in Red clover was optimum in 400-ind./㎡.