This paper reports the flocculated fermentation as a new method of propionic acid production.Propionibacterium shermanii W125 were used,29.0g/L propionic acid was accumulated in batch fermentation.In the subsequently established fed batch semicontinous fermentation,35.4g/L propionic acid was accumulated,raised to 122% and the conversion rate of glucose to propionic acid reached 51.56%,the volumetric productivity reached 0.37g/(L/h)during the 250 hours running cycle.