The types,distribution and numbers of glandular hairs on the leaves at the upper,middle and lower nodes of the branches at vegetative and productive stage of Elsholtzia ciliata (Thunb.) Hyland were investigated by means of optical microscopy and scanning electron microscope technology;The process of secreting flavonoids by the glandular hairs were studied based on histochemistry method and fluorescence microscopy.The results showed that:(1)leaf epidermis of E.ciliata possessed peltate and capitate glandular hairs.Mature capitate glandular hair included basal cell,stalk cells and head.The head was small and hemispherical,with a diameter of (20±2) μm. Head of nearly mature peltate glandular hair was large and shield-shaped,with a diameter of (60±5) μm.(2)Glandular hairs distributed in abaxial and adaxial leaf epidermis of E.ciliata.The number of glandular hairs of the adaxial epidermis was more than that of the abaxial epidermis.Peltate glandular hairs were mainly distributed in the abaxial epidermis and capitate hairs were distributed in both sides of the leaves;the density of glandular hairs decreased with the lower of node.At the same node,the density of glandular hairs on the leaf at vegetative growth stage (283.9 per mm²) was higher than that at reproductive growth stage (194.4 per mm²).(3)Flavonoids can be secreted by peltate and capitate glandular hairs.With glandular hair development and maturation,flavonoids accumulated gradually in the head.This study provides a reference for further study on the mechanism of secreting essential oils by the glandular hairs of E.ciliata,and also provides a theoretical basis for determining the best sampling time to extract the flavonoids from the leave of E.ciliata.