The biomass pulse-response method was established and the biomass transmission index was introduced as a quantitative parameter for evaluating the biomass-adsorbent interactions in the expanded bed.With baker’s yeast intact cells and cell debris as the model biomass and anion exchanger Streamline DEAE as the model adsorbent, a series of factors were investigated to optimize the evaluation method.The appropriate operation conditions were chosen as the OD 600 of biomass pulse at the range of 0.5—0.6, and pulse loading at 80% volume of sedimented bed, expansion factor at 2.5.The method was then used to study the influence of ionic strength of fluid phase on the biomass-adsorbent interactions.The consistent results and slight measurement errors demonstrated that the biomass pulse-response method established in the present work is feasible, reliable and effective for quantitative evaluation of biomass-adsorbent interactions in the expanded bed.