With the Greening Roll as matrix material, we investigated the growth and physiological characteristics of Vitex negundo growing on the sand land, slag yard and concrete roof to clarify the mechanism responsive to paclobutrazol treatment with different concentrations (0, 100, 200, 300 and 400 mg·L^-1 paclobutrazol). The results showed that: (1) the height and biomass of plant decreased, as well as basal diameter, crown, leaf area, root range, taproot length and taproot diameter, while the leaf length to width ratio and rootshoot ratio increased. The leaf relative water contents, chlorophyll contents, soluble sugar and soluble protein contents increased after paclobutrazol treatment. And malondialdehyde (MDA) contents decreased. (2) The growth and physiological responses of V. negundo to paclobutrazol treatment under three site conditions were significantly different. The comprehensive evaluation of indices by membership function method indicated that the appropriate paclobutrazol concentrations of sand land, slag yard and concrete roof were 400 mg·L^-1, 300 mg·L^-1 and 100 mg·L^-1, respectively. (3) When the paclobutrazol concentration of slag yard and concrete roof reached 400 mg·L^-1 and 300 mg·L^-1 respectively, the plants had gotten hurt. The tolerance threshold for paclobutrazol of plants on sand land was higher than that on slag yard and concrete roof. The study indicated that paclobutrazol could enhance stress resistance and environment adaptability of V. negundo by regulating plant morphology, adjusting biomass allocation, improving the osmotic adjustment and antioxidant activities. The differences of site conditions should be considered to utilize the paclobutrazol better and safely with the appropriate concentration and dosage in artificial vegetation restoration and construction.