This work deals with the investigation of tray effiapplication in the suspension catalytic distillation (SCD) process. The experimental data of tray eficiency under dif-ferent conditions were measured by utilizing the desorption of oxygen dissolved in water by air. A method of estimationof tray efficiency for the gas-liquid-solid three phases was put forward and its suitability was also verified. This methodwas developed on the basis of the AIChE method for gas-liquid two phases. As an application example of this modifiedAIChE method, the SCD process for synthesizing cumene, based on equilibrium stage (EQ) model incorporatingtray efficiency, was simulated.