Abstract: This is a parametric study for multi-phase particle in cell (MP-PIC) simulation of bubbling fluidized beds with Geldart A particles using the open source MFIX program. The main parameters have been studied including drag models, grid resolution and number of particles per parcel (PPP). And the calculated axial/radial solid distribution and bed height are compared with the experimental data for validation. It is shown that the drag model can significantly affect the calculation results of bubbling fluidized bed with Geldart A particles. Specifically, the Energy Minimization Multi-scale (EMMS) bubbling drag model can predict right bubbling phenomenon and also improve the accuracy compared to the homogeneous drag model. Bubble analysis shows that there exists a stable average bubble diameter when the bed becomes stable. The average bubble circularities are about 0.5 for the two bubbling bed studied in this work, even though they have different average bubble diameter. Parameter analysis shows that the accuracy of the calculated results improves with decreasing grid size or PPP. There exists a threshold value for grid size/PPP, below which, grid/PPP independent result can be obtained. The PPP plays the similar role to grid resolution in MP-PIC simulation.