In this paper, a rapid, simple and sensitive HPLC method to screen and accurately measure the level of phenyllactic acid (PLA) in lactic acid bacterial (LAB) MRS culture supernatant was established. Using this method, we successfully identified a Lactobacillus plantarum strain YM-5-2 which could highly produce PLA, the yield of PLA by L. plantarum YM-5-2 reached 147.91 mg/L. To our knowledge, this is the highest PLA-producing LAB strain when growing in MRS broth without any fermentation conditions optimizing, and it is the first report on antibacterial factor produced by LAB isolated from 'Douchi'-a traditional fermented soybean food in Yunnan Province, China. Antimicrobial activity of L. plantarum YM-5-2 suggested that it may be used as a biopreservation microbe in the food industry. 漏 2011 IEEE.