In this study, laser scanning confocal microscopy (LSCM) was used to determine the location and relative quantity of flavonoids in the leaves of Apocynum venetum L. from the top, middle and basal parts of the branch. The leaves of the plants of one, two and three years old, separately, were collected in July. ANOVA and LSD test were employed in the statistical analysis. The results indicated that flavonoids located mainly in xylem conduit of vein, collenchyma, epidermic cells and cuticle. The data of flavonoids contents under statistical analysis showed that difference existed in the leaves of different parts and different ages. This study provided the reliable scientific material about the analysis of the ecological and the exploitation of the leaves of Apocynum venetom L.