Abstract: The ultrastructure changes of the developmental stigma hairs of Liriodendron chinense (Hem-si. ) Sarg. have been studied with their exudate examined by cytochemical methods. The stigma belongs to the "wet type". The stigmatic hairs develop from the adaxial side of uncuticular epidermal cells which are mostly unicellular in structure. The secretion of stigma is closely related to the or-ganelles of stigmatic hair cell. In the early stages, the laminated layers are related to the rough endo-plasma reticulum, and the osmiophilic granules are related to mitochondria. However, the plastids have not yet fully developed. After the early stages while the tubular type of SER is formed and starch grains in the plastids become degraded, the secretion of lipid droplets begins to appear, The cytochemical analysis of the exudate is shown as follows: It is not possible to stain polysaccharide, proteins and lipids in the exudate of the early stages by using periodic acid-schiff’s reaction, Coomasie Brilliant Blue R-250 and Sudan Black B respectively. Only lipids show strong positive reaction at its later stages.