Polycyclic Aromatic Hydrocarbons (PAHs) are a large group of chemicals that mainly produced by incomplete combustion of coal, gasoline, wood, garbage or other organic materials. PAHs consist of a number of toxic compounds which have great harmful effects on plants, animals and human health. It has been commonly recognized that trees have great potential for the scavenging, storage and purification of relatively large amounts of PAHs. Accumulation of PAHs in vegetation depends on the properties of the particular PAHs as well as on the properties of the accumulating surface. However, while most research focused on accumulation capacity of trees on PAHs, less know the relationship between PHAs concentration and leaf surface structure. In order to examine the relationship between accumulation of PAHs and leaves′ structure of major tree species in southern China, the composition and accumulation of PAHs in leaves of four major urban street tree species (Cinnamomu camphora, Magnolia grandiflora, Opsmanthus fragrans and Redrlowered loropetalum) were investigated in Changsha city, Hunan province, China. Structural features of the leaves, including leaf stomatal density, stomatal length:width ratio, leaf width:length ratio, and leaf area, were also measured. The objectives of the research were to (1) determine the composition and concentration of PAHs in leaves of the selected four tree species, (2) examine the relationship between PAHs concentration and surface structures of leaves of the four urban street tree species, and (3) compare the accumulation capacity of PAHs among the four tree species The results showed that all 16 priority PAHs were detected in the leaves of the four tree species, but the three-ring and four-ringf PAHs dominated, in particular for Phe. The highest total concentration of PAHs (11.13mg?kg-1) was found in the leaves of Redrlowered loropetalum while the lowest (3.66mg?kg-1) in the leaves of Opsmanthus fragrans. Total PAHs concentrations were 7.58 mg?kg-1 and 4.34 mg?kg-1 in the leaves of Cinnamomu camphora and Magnolia grandiflora, respectively. Except the tree species of Opsmanthus fragrans, a closely relationship between leaf stomatal density and accumulation of PAHs was found in other three tree species′ leaves. Because of low temperatures in fall and winter seasons, higher leaf stomatal density resulted in higher accumulation of PAHs in leaves. There were significant positive correlations between leaf stomatal length:width ratio, leaf width:length ratio and PAHs concentration in leaves of all test tree species. But a negative correlation was found between leaf area and PAHs concentrations in leaves. Our results indicated that structural characteristics of leaves of urban tree species were important factors in affecting the accumulation of PAHs in study area.