Abstract: In order to understand the development characteristics of the fruit of Cammellia magnocarpa, the fruits were periodically picked and the transverse and longitudinal diameter, dry weight, oil content and fatty acids content of the fruits were measured. The results showed that the fruit shape of C. magnocarpa expanded rapidly in the early period of fruit development, and the fruit size would no longer change after late July. The fruit dry matter kept basically linearly growing, and the seed dry matter accumulated from late June to late October. The seed oil accumulated from late July to late October as well. The seed oil content showed a linear growth and was up to 29.72% when it came to harvest. The content of various fatty acids in seed oil changed with fruit growing. The content of oleic acid and stearic acid increased while the content of palmitic acid and linoleic acid decreased. On the whole, the content of unsaturated fatty acids increased while the content of saturated fatty acids decreased accordingly.