Abstract: Objective: Acid amylase producing endophytic fungus was screened from Salvia miltiorrhiza Bge. And its enzymatic properties were studied. Method: Amylase producing strains with high activity were screened by starch solid medium and fermentation medium, and identified by morphological observation and ITS sequence analysis. Results: 5 strains with higher amylase activity were screened from 50 endophytic fungi.Among them, the strain ZDH2-2-1-1 produced the highest activity of amylase, and the enzyme activity reached 117.63 U/m L, which was identified as Alternaria alternata. The enzyme properties showed that the optimal reaction p H of amylase from the strain ZDH2-2-1-1 was 4.0, the optimal reaction temperature was55 ℃, and the strain ZDH2-2-1-1 had good thermal stability, p H stability and a wide spectrum degradation ability of raw starch.By thin layer chromatography, the results showed that the enzymatic hydrolysis product of amylase produced by ZDH-2-2-1-1 was glucose.Conclusion: Endophytic fungi from Salvia miltiorrhiza Bge.can produce heat-resistant acid amylase, which has great development potential in the deep processing of raw starch.