Abstract: The application effects of two kinds of widely-used plant growth regulators i.e., CCC and PP333 on growth of new shoot length, branch diameter and other growth indices of Castanea mollissima saplings were testified by random block design experiment. The results showed that there were extremely significant differences in the length growth of new shoots both in each cultivar and among the cultivars when the 2 tested plant growth regulators were applied. The regulators could also significantly affect the growth of branch diameter. It was showed by the experiment that there were interactions among the regulator treatments and the cultivars. Comparatively speaking, CCC had stronger effect on the growth of new branches. 100 μg/g of CCC could well inhibit occurrence of water sprouts and enhance effective accumulation of the organic nutrition.