Abstract: Baker’s yeast was treated as modeling microorganism which owned a large particle volume.The subsidence phenomenon baker’s yeast during turbidity measurement process was studied.The stability of the baker’s yeast was improved by adding hydrolyzable anionic polyacrylamide (HPAM) into the suspension.A standard curve between turbidity and yeast concentration was established of in the thickening system.The results showed that the settlement of the yeast cells was effectively prevented by HPAM, the turbidity exhibited good linearity over the range from 0 to 4.9×106 cell/mL with a correlation coefficient of 0.9976, and the detection limit was 1.0 ×104 cell/mL.The average recovery was 100.99%, indicating that this method possessed good accuracy for yeast and was suitable for application in microbial biomass quantitative detection in liquid environment.