Abstract: The relationship between teak seedling density and stump growth,formation of main root,seedling yield per unit area and seedling quality are studied through adopting biomathematics method.35 mathematic models are established using 10 curve equations i.e.exponential function,power function,logarithmic function etc.. The results show that:1. The seedling growth above and under the ground in Jiangfeng good site are far inferior to the growth in Guangzhou poor site at the same seedling density.The difference between them will be increased as density increases. THis is why there are differences between two sites in sunshine/day and coordination of water and hot.2.Adjusting seedling density on the basis of different ecological condition in different sites is more effective than prolonging the time of breeding seedlings in one site to increase seedling yield and quality.3.The suitable seedling density in Jiangfeng and Guangzhou are 100～200 and 300～400 seedlings per square meter respectively. There are four density classes(50 seedlings per square meter is taken as one class).The best seedling quality and yield could be got by adjusting the seedling density to the most suitable condition.