A mathematical model has been formulated based on the combined continuous and discrete particle method for investigating the sedimentation behaviour of microparticles in aqueous suspensions,by treating the fluid phase as continuous and the particles phase as discrete,thus allowing the behaviour of individual particles to be followed and the evolution of the structure of the particle phase to be investigated as a function of time.The model takes into account most of the prevailing forces acting on individual particles including van der Waals attractive,electrostatic repulsive,gravitational,Brownian,depletion,steric,contact and drag forces.A code has also been developed based on the model.This paper reports some preliminary modelling results of mono-dispersed microparticles settling in aqueous suspensions under various conditions.The results show the short time dynamics of the fluid phase,which has a similar order of magnitude to the particle phase.Such short time dynamics could bear significance to processes such as particle aggregation when their size becomes very small.Preliminary analyses of the results have also been carried out on the evolution of particle settling based on a newly proposed parameter,local normalised volume fraction(LNVF). A mathematical model has been formulated based on the combined continuous and discrete particle method for investigating the sedimentation behavior of microparticles in aqueous suspensions, by treating the fluid phase as continuous and the particles phase as discrete, thus allowing the behavior of individual particles to be followed and the evolution of the structure of the particle phase to be investigated as a function of time. The model takes into account most of the prevailing forces acting on individual particles including van der Waals attractive, electrostatic repulsive, gravitational, brownian, depletion, steric, contact and drag forces. A code has also been developed based on the model. This paper reports some preliminary modeling results of mono-dispersed microparticles settling in aqueous suspensions under various conditions. The results show the short time dynamics of the fluid phase, which has a similar order of magnitude to the particle phase. Sudch short time dynamics could bear sig nificance to processes such as particle aggregation when their size becomes very small. Preliminary studies of the results have also been carried out on the evolution of particle settling based on a newly proposed parameter, local normalized volume fraction (LNVF).