In order to obtain biological preservatives for application in food preservation， antibacterial functional microorganisms were screened and their antibacterial substances were studied. The Oxford cup method was used to screen the antibacterial functional microorganisms， and to study their inhibitory spectrum using the area of the inhibition circle as an indicator. The pH， temperature and UV irradiation stability of the antibacterial fermentation broth was investigated using the change in antibacterial potency as an indicator. The acid exclusion test and high performance liquid chromatography (HPLC) were used to study and analyse the antibacterial substances. It was found that among the 16 strains of acid-producing bacteria with antibacterial ability screened from sauce mash and kimchi， Staphylococcus saprophyticus JL03 and Lactobacterium plantarum L04-1 showed excellent antibacterial effect and broad-spectrum antibacterial properties. The antibacterial fermentation broth of the two strains decreased from 5 730.69 IU/mL and 5 772.35 IU/mL to 5 190.12 IU/mL and 5 122.20 IU/mL at pH 3.0， respectively. All retained more than 85% of their initial antibacterial activity， indicating good pH stability. When the two bacterial antibacterial fermentation broths were treated at 100 ℃ for 20 min， the antibacterial potency of JL03 decreased from 5 730.69 IU/mL to 4 588.52 IU/mL， retaining more than 80% of the initial antibacterial activity. In contrast， the antibacterial activity of L04-1 decreased by 44.11%， indicating that the thermal stability of JL03 antibacterial fermentation broth was better than that of L04-1. After 3 h of UV irradiation， the antibacterial potency of the two bacteria decreased from 5 730.69 IU/mL and 5 772.35 IU/mL to 4 697.29 IU/mL and 4 437.52 IU/mL， respectively. All of them retained more than 70% of their initial antibacterial activity， indicating that they have good antioxidant properties. The acid exclusion test revealed that the antibacterial substances of the two strains were mainly acids， and the inhibitory capacity of acidic substances accounted for 58.03% and 64.32% of the total inhibitory capacity， respectively. HPLC analysis of the antibacterial fermentation broth of the two bacterial strains fermented for 72 h showed that the main acids were oxalic acid， L-malic acid， lactic acid， acetic acid， citric acid， succinic acid and fumaric acid， with a total content of 9.64 g/L and 13.46 g/L， respectively. Correlation analysis showed that L-malic acid (0.43 g/L) and lactic acid (6.76 g/L) were significantly and positively correlated with the antibacterial potency of JL03 antibacterial fermentation broth (P < 0.05). Lactic acid (5.75 g/L)， succinic acid (1.32 g/L) and fumaric acid (0.32 g/L) were significantly and positively correlated (P < 0.05) with the antibacterial potency of L04-1 antibacterial fermentation broth. Screening of antibacterial microorganisms and the analysis of key antibacterial substances have laid the foundation for improving the antibacterial performance of antibacterial microorganisms and their application in the field of food preservation.