Abstract: Camptotheca acuminata, a rapid growing tree indigenous to south China, which can produce a kind of anticancer secondary metabolite, camptothecin(CPT). CPT is classified as a modified monoterpenoidindole alkaloid that has attracted great attention for its significant role in antitumor activity. It is presumed that CPT is one of the defence compounds of C.acuminata, but the contents of CPT are usually very low. Previous reports have shown that environmental factors such as light intensity can affect plant growth and metabolite synthesis. To enhance CPT yield in C. acuminata, we observed the effects of light intensity on CPT production in the leaves of C. acuminata. We use three levels of light intensity, namely L1 300, L2 500, L3 800 μmol/(m²·s). The samples were collected from the third to fifth leave from the seedling top at the 7, 14, 21 and 28 days after treatment. The results were shown as follows. At L1, there were great increments in the seedling height and caliper. With the increase of light intensity, the root cap ratio increased in the beginning and then decreased, while the biomass generally showed a decreasing trend. The seedlings possessed the highest soluble sugar and soluble protein accumulation at L3. Both L1 and L3 had positive effect on TDC activities, and in the meantime, there was a great enhancement in CPT concentration and yield per plant at L1. This may have important implications for the production of the antitumor drug CPT in plantations at an industrial scale.