The paper used ANSYS numerical simulation software and Drucker-Prager yield criterion and carried out reasonable assumption so as to establish compaction model of compaction grouting pile in the soil; it studied the influence of grouting pressure on compaction grouting pile radius through changing the grouting pressure within the common scope of the pressure used in engineering,and obtained the relation between the compaction radius with grouting pressure by means of curve fitting.Combining the field test of compaction grouting pile, the paper got the conclusion which is basically consistent with the numerical simulation.The results can provide a reference for site construction.