Coarsening of solid particles in a solid-liquid two-phase system with high solid volume fraction is studied using the multiphase-field model. The influences of interfacial wettability and solid volume fraction on growth exponent, coarsening rate, and particle size distribution (PSD) are analyzed. It is found that the growth exponent is independent of the volume fraction, while the coarsening rate constant and the PSD are closely related to the interfacial wettability and the solid volume fraction. Under the completely wetting condition the coarsening rate constant increases with volume fraction increasing, but this variation is insignificant under the incompletely wetting condition. Moreover, when the wettability is low and volume fraction is high, the coarsening rate may also decrease with volume fraction increasing. The simulation results also show that with the increase of volume fraction, the peak frequency decreases and the PSD becomes broader, but the fall of the peak frequency under the incompletely wetting condition is slower than under the completely wetting condition. The simulation results provide an insight into the discrepancy between different experimental observations.