Alcimandra cathcartii (Hook.f. & Thomson) Dandy (Magnoliaceae) is a valuable woody species and listed in Vietnam Red Data Book (2007) as category CR BI+2b,e because of its extremely rare and unique gene. The survey results from the research showed that A. cathcartii is distributed from alttitude of 2.000 - 2.600 m, along the path from Tram Ton to Fanxipan peak of the Hoang Lien National Park. In forest community, A. cathcartii is dominant and plays an important role in plant composition. It often occurs with some relative species like Elaeocarpus griffithii, Castanopsis phansipanensis, Rhododendron sinofalconeri, Machilus odoratissima and Rhodoleia championii. The density of A. cathcartii in the forest is quite high, ca. 200 - 250 trees/ha. A. cathcartii can regenerate from both seeds and stump shoots, but usually in seeds and rather good, ca. 560 - 2.720 saplings/ha. Therefore, these are good points for conservation of rare and unique A. cathcartii at the Hoang Lien National Park.