Abstract:Re-introduction method, introducing the human-bred seedlings of a species into its natural distributed area, can effectively conserve the endangered and rare species in natural situation and may help to reconstruct a degraded ecosystem associated with species loss. Re-introduction aims to improve ecosystem diversity and community stability, to rebuilt sustainable populations, and consequently to become an effective method in conservation of endangered and rare species, as well as the early-developed conservation methods including in-situ and ex-situ conservation methods. Re-introduction has been developed internationally for a relatively short time with little highly successful case, which could mainly attributed to inappropriate environmental factors in the reintroducing sites and lack of knowledge about the biology and ecology of the target species. In present paper, by reviewing several re-introduction case-studies and some criterions of international organizations of plant conservation, we discussed the detailed technology and evaluation of the effectiveness about the re-introduction method (mainly focus on endangered Orchid) and summarized the main feasible conditionality of a successful re-introduction. A better understanding of the biology and ecology of the conserved plant and the selection of proper reintroducing sites are emphasized as major elements for the success of re-introduction. Furthermore, the main types and elements of re-introduction method in orchid conservation are also explained. We pointed out that the re-introduction of endangered and rare orchids is particularly difficult since they are often having a deep symbiosis with other organisms such as fungi and host plants. Before re-introduction of an orchid is carried out, we should provide the mutualist either in the environments or implanting into the conserved orchids, as well as constructing the suitable conditions in introducing sites for them. Finally, we proposed some future developments of re-introduction method, which can be used as a guide to the species conservation in a larger scale, not only for the orchid but also for the other species.