Abstract: In this study,an endophytic fungi X1 that produces orange pigment was isolated and screened out from Dendrobium candidum.In order to clarify the species of this strain and the stability of its natural pigments,and the strain was identified as Neurospora sp.based on molecular biology.The orange pigment which produced at this strain has the highest absorption peak at 400nm.It is show that when the pigment is placed in ultraviolet light for 6 h,the absorption value increased,indicating a color enhancement effect.It is not affected much at pH 2-8 and 20-100 ℃.Furthermore,H₂O₂ and Na₂SO₃ have strong destructive power to the pigment though several common additives have no effect on the pigment．In the metalions,Fe³⁺,Zn²⁺,Cu²⁺,Ca²⁺and Mn²⁺ have color protection or burnish effect on the pigment.Meanwhile ,10%NaCl and 15% glucose solution also have a significant hyperchromic effect on it．This study has theoretical and practical importance for the separation of endophytic fungi and extraction process of fungal pigments.

Key words: Dendrobium candidum, endophytic fungi, identification, pigment, stability