Abstract: Alternaria is one of the main pathogenic bacteria of fruit black spot and severely impairs the postharvest storage process of fruit.Alternaria was isolated from the pear and apple of a orchard in south Xinjiang and identified by morphological characteristics and molecular biological methods.110 strains of lactic acid bacteria ( LAB) from Xinjiang dairy products were performed to detect the inhibitory activity on Alternaria and solid cake, stationary and shaker broth were used for fermentation.The results showed that 2 strains of Alternaria named Alternaria gaisen and Alternaria tenuissima were obtained.4 strains of LAB with inhibitory activity on Alternaria were screened out and 3 of them were Lactobacillus pentosus, the other one named Lactobacillus paracasei.At the same time, the highest inhibitory activity on Alternaria was from shaker fermentation broth and the diameter of the zone of inhibition was up to 21.17 mm.It provided a theoretical basis to apply LAB from dairy products to control the black spot disease caused by Alternaria in the postharvest.