Morphological characteristics and secretory structures of leaf and sepal of Ocimum basilicum var. basilicum Linn. at full flowering stage were observed with light microscope and scanning electron microscope. The results show that there are glandular hairs and non-glandular hairs on both leaf and sepal of O. basilicum var. basilicum， and glandular hairs are its secretory structures. Under light microscope， there are many bright yellow internal dissolved substances in the top of glandular hairs on sepal， which might be secreted volatile substances. Capitate glandular hairs and peltate glandular hairs can be observed on the leaf surface under scanning electron microscope， in which， the latter are the major secretory structures of volatile substances on leaf； there are differences in distribution density of different types of glandular hairs on the same leaf， and there are 7.7 peltate glandular hairs and 1.4 capitate glandular hairs per unit area （1 mm×1 mm） of leaf； secretory cells in the top of peltate glandular hairs on the same leaf can be classified into two-split type， four-split type， and five-split type， which may be associated with the development degree of glandular hairs. The study lays the foundation for futher exploration the relationship between secretory structures and volatile oil components of O. basilicum.