Abstract: The baiji, Lipotes vexillifer is a rare and highly endangered river dolphin indi-genous to China and has a currently estimated population size of about 200 indivi-duals. On the basis of the known characteristics of baiji, and the environment of the Changjiang(Yangtze)River which is the only present-day habitat of baiji,we have proposed to establish a semi-natural reserve for the baiji at Tian-e-zhou(Swan)which is an oxbow segment of the Changiiang River near the city of Shishou in Hubei Province. This paper reports the findings from a 4-year feasibility study co-nducted by our institute on Tian-e-zhou and is mainly based on the physical and cliemical parameters of water quality monitoring,aquatic biological situation and biological productivty,fish prodution. Comparisons of our findings from the Oxbow segment and from the Changiiang River are presented.Five finless porpoises,Neophocaena phocaenoides,were introduced into the oxbow as a model testing group.After about two years'observation and monitoring,our results indicated that the oxbow is ideal as a semi-natural habitat for the fin-less porpoises.It is suggested that the oxbow may be used as a feasible semi-natural reserve for the propagation and then for the conservation of the baiji as a target species.