An inner-bioreactor rapid filtration sampling probe was designed to resolve the problems of continuous sampling the fermentation broth in on-line measurement the fermentation process. The probe consists of a support, a plug valve, an O-ring, a filter membrane and a pipe cover. It can be inserted directly into the bio-reactor withstanding high-temperature sterilization before fermentation, or preventing the bacteria's invasion during sampling. Fermentation broth in tank is cross-flow filtrated by a cylindrical ceramic membrane which is used as filtration membrane, and then the sterile permeated liquid is transported to the analyzer by a peristaltic pump. The sampling experiments using this device was described for sampling glucose solution indicating it is suitable for fermentation online sampling. The sampling rate is up to 3. 0 mL/ min, glucose permeability maintains 100% , and the delay time caused by the probe is about 2 min.