The critical suspension speeds of floating particles in a gas-liquid-floating particle three-phase system were measured in a multiple-impeller agitated vessel. Three types of impellers, i.e., simple axial-flow impeller upflow (SPU) and downflow (SPD), disk turbine (DT) and wing turbine (WT), twelve types of baffles and three kinds of gas spargers were used. The influences of impeller types, baffle configurations, gas spargers, gas superfacial velocity and particle loading on the critical suspension speeds of floating particles were systematically investigated. The optimum regressions of critical suspension speeds were respectively obtained for some better combinations of impellers, bafffles and spargers, such as (a) the 45SPU+45SPD+DT triple impellers, two high-level baffles and two low-level baffles (symmetric allocation), gas spargers, (b) the 45SPU+45SPD+DT three-impeller, standard baffle and small gas sparger. Their errors were smaller than 11 %.