In order to develop a numerical tree model for calculating the effects of solar shading by a tree, it is important to focus on sunlight distribution, which is the light falling onto ground through the tree. Sunlight on the ground has not only a psychological impact but also a physical impact, such as increasing the surface temperature distribution. Thus, this paper discusses sunlight distribution on the ground through a numerical analysis of the differences between tree species, using CG tree models. Three deciduous tree species, with different crown shapes, were chosen. There are popular shade trees in Japanese streets. The sunlight ratio distribution of each tree was computed by the ray-tracing method on the summer solstice in Tokyo at 12:00 and 17:00. It is clear from this analysis that the tree's geometrical shape, which depended on the species, created different tendencies of sunlight distribution on the ground at each solar altitude. The oval-shaped tree showed little change with the different solar altitudes. On the other hand, the cone-shaped and vase-shaped changed depending on solar altitude.