More than 400 yeast strains were examined for their flocculation, and five of them displayed strong flocculation. The 5 strains were divided into two groups which are Flo 1 and NewFlo phenotypes on the basis of their response to sugar inhibition. Related physiological and biochemical characteristics of the two phenotypes' strains were studied. The results showed that the flocculation of Flo 1 phenotype was only inhibited by mannose; it was sensitive to high temperature (70 degrees C), pronase E, trypsin, whereas tolerant to pronase K, chymotrypsin, Ca2+, pH; the flocculation of NewFlo was inhibited by many sugars, such as glucose, maltose, sucrose, mannose; it was sensitive to high temperature (70 degrees C), pronase, Ca2+, pH. The Calcium concentration and pH value of the optimum flocculaton of the Flo1 and NewFlo phenotypes strains were respectively 10 mmol/L-1 mol/L; 3.0-4.5.