This essay discusses that 45 species of rare and endangered plants were introduced in Nanjing in ex situ conservation, including Parrotia subaequalis, Sinojackia xylocarpa, Berchemiella wilsonii and Heptacodium micronioides located in the subtropical area. The conservation results have shown that the similaries of ecological conditions between the introduced habitat and original habitat are one of very important factors. The more similar are habitat conditions between introduced habitat and original habitat, the better do the plants grow. It is also known that the potential adaptability of these introduced plants should be observed. For example, though Tapiscta sinensis grows in moisture hillside fields in the original habitat, it can be planted in the dry habitat in full light in our garden.