Abstract: Endophytic fungi in plants have the potential of producing natural active substances and it is one of the sources of natural pigments.In this study,endophytic fungi RML6 is screened out from the leaves of  Lycium ruthenicum Murr.,and the strain is identified as Coprinellus radians,The yellow pigment which produced at this strain has the highest absorption peak at 341 nm.The stability of the yellow pigment which produced by the endophytic fungus RML6 of Lycium ruthenicum Murr was investigated from the aspects of temperature,pH,light,metal ion,oxidant and reducing agent.The results show that the pigment has no significant change in the light absorption value of yellow pigment for 8 hours under natural light,but it is less sensitive to UV storage.It is not affected much at pH 6-10 and 20-100  ℃.In the metal ions,Na⁺ ,K⁺,Mg²⁺,Cu²⁺ 、Fe³⁺ have color protection or burnish effect on the pigment,Zn²⁺,Mn²⁺,Ca²⁺ have a significant effect on the pigment. H₂O₂ and NaHSO₃have strong destructive power to the pigment though several common additives have no effect on the pigment.Meanwhile ,sucrose also has a significant hyperchromic effect on it.So the pigment can be used for a wide range of applications.

Key words: endopHytic fungi, yellow pigment, stability, Lycium ruthenicum Murr.