Abstract: One rare actinomycete strain,which had strong activity for restraining NO synthesize enzyme,isolated from a soil sample collected from Hekou,Yunnan Province.Based on our polyphasic studies,including its morphology,physiological and biochemical characteristics,chemotaxonomy and 16S rDNA sequence analysis,it was proposed it as a new species of genus Nocardia and named it as Nocardia alba sp.nov..Strain YIM 30243T grew well on most test media.The color of the aerial mycelium were from yellow-white to pink-white,the substrate mycelium were from yellow-white to yellow-brown, and the aerial and substrate mycelium all irregularly fragmented.