The hollow independent composite pile with super-large diameter is a new type of pile foundation jointly carried by a hollow pile, an external cement mixing pile, and grouting soil around the pile. Numerical computation and theoretical calculation were performed in this paper to determine the vertical ultimate bearing capacity of this type of pile under different conditions in Jianghuai area of Anhui Province. Introducing the concept of equivalent elastic modulus to equate the non-homogeneous elastic modulus as the homogeneous elastic modulus will significantly reduce the complexity of calculating the vertical ultimate bearing capacity. Pile diameter and pile length have great impact on the vertical ultimate bearing capacity. The impact factor D_L which takes pile diameter and pile length into consideration makes the modified theoretical formula more reliable.