The axial stress and axial displacement distribution curves of reinforced mixing single pile are researched by ANSYS software; and the differences of the single pile ultimate capacity of reinforced mixing pile between different core pile length and area replacing ratio are analyzed; It compared and analyzed envelope diagrams of bending moment and shear of reinforced mixing pile in different core pile length and area replacing ratio under seismic response. Some conclusions which may be of some value for design and construction of reinforced mixing pile composite foundation are drawn