In the gas-liquid-solid fluidized bed reactor (FBR) under super-condensed mode, the injection of liquid causes the particle agglomeration that leads to a complicated and unstable fluidization system. In this work, a probabilistic stability model is developed on the basis of a three-particle collision theory to describe such mode. The criterion of the model is achieved by analyzing the particle interaction, relative velocity distribution, and energy transfer in particle collision. The model error mainly originates from by the simplification of the actual system. The developed model is applicable to the case that a droplet completely spreads on the particle surface, that is, the solid-liquid contact angle is less than 40 degrees. We then systematically verify the current model by comparison with the experimental data from the literature. The developed model provides an application prospect in reactor design and scale-up. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.