In order to improve the antioxidant activity and flavor of snow pear juice， pear juice was fermented with Lactobacillus casei Y5-2b， Lactobacillus plantarum C17 and Lactobacillus acidophilus CH-2， respectively. Physicochemical properties and antioxidant activities were characterized. And high-performance liquid chromatography and gas chromatography-ion mobility spectrometry (GC-IMS) was applied to analyze the nutrients and aroma components. Results showed that the three strains had good growth and metabolism in pear juice. Moreover， the proliferation metabolism of Y5-2b and C17 showed better performance， with a stable number of viable bacteria reaching 9.0 lg CFU/mL at 20 hours. The antioxidant activity of fermented pear juice increased significantly(P<0.05). The sugar content decreased， with glucose being the most consumed and the utilization rate ranging from 5.29% to 8.85%. Partial organic acid content showed a decrease， with no malic acid detected in groups Y5-2b and C17. There was no significant difference in malic acid content between the CH-2 group and the unfermented group (118 mg/100 mL)， and the citric acid content decreased by 33.65%， 42.97%， and 38.71% respectively after fermentation. Different lactic acid bacteria fermentation had different effects on the content of phenols in pear juice， mainly arbutin， catechin and rutin. A total of 44 aroma components were identified from juice samples， of which 3-hydroxy-2-butanone， n-butyraldehyde， butyric acid and other characteristic flavor substances with fruit aroma increased in varying degrees after fermentation. In conclusion， lactic acid bacteria endowed the pear juice with abundant substances， flavor and high antioxidant activity， which provides a certain theoretical basis for lactic acid bacteria fermentation of pear juice.