At present, the plant species used for green roof are limited. In order to further expand the plant species used for green roof, it is particularly important to explore the adaptability of different plant species. In this study, 6 species of Crassulaceae (Kalanchoe blossfeldiana (K. blossfeldiana), Sedum lineare (S. lineare), Hylotelephium erythrostictum (H. erythrostictum), Phedimus aizoon (P. aizoon), Rhodiola rosea (R. rosea) and Sedum sarmentosum (S. sarmentosum)) were selected and planted on the stainless-steel planting rack on the roof with a substrate thickness of 15 cm. After normal maintenance and management for 1-month, continuous water deficit treatment was carried out. The physiological properties were measured at 0, 10, 20, 30 and 40 days, respectively. The results showed that: (1) The 6 species of Crassulaceae grew normally and well within 0-20 days. At 30 days, K. blossfeldiana had the most severe wilting rate (53%) and S. lineare had the least wilting rate (14%), but still maintained basic ornamental value. After 40 days of water deficit treatment, all the plants lost their ornamental value. (2) Among the 6 species under different water deficit treatment times, S. lineare and P. aizoon ranked between 1-3 in the 0-20 days when the water deficit degree was mild, and still ranked first and second in the 30-40 days when the water deficit was severe, with the best performance throughout the whole process, which could adapt to extensive green roof and did not need too much management. S. sarmentosum and K. blossfeldiana ranked 4-6 in the membership function under 40-day water deficit stress, with the worst performance. They are not suitable for extensive green roof and need careful management. In addition, considering the ornamental effect and ecological benefits of green roof, except K. blossfeldiana and S. sarmentosum, the other four plant species are suitable for the application of extensive green roof.