A endophytic fungus with lead and cadmium tolerance was isolated from the two-year-old healthy Davidia involucrate stem. It was initially identified as Alternaria sp. According to the characteristics of morphologythe optimal medium was PDA for the growth of the fungus. Temperature, pH, nitrogen sources and carbon sources affected the growth of the fungus. The fungus could grow at 15~35 ℃.The optimal growth temperature was 25~35 ℃. It was adaptable to the properties in a broader pH value range. It could grow well between pH 5.0 and pH 9.0. Many carbon sources and nitrogen sources tested could obviously make the fungus grow. The best carbon source was glucose, soluble starch, mannose or sugar. The best nitrogen source was sodium nitrate. It could grow on the Czapek Agar with a concentration of 1 000 mg/L Pb(NO2)2 or 100 mg/L CdCl2.2.5H2O.The results showed that the fungus had stronger adaptability under lead stress and cadmium stress.