The pile-soil stress ratio is an important design parameter of composite foundation, and the calculation of the pile-soil stress ratio of composite foundation with mixed core pile is a difficult engineering problem. For long core mixing pile, the section method is used to divide the upper equal core pile and the lower rigid pile. The former adopts the sectional nonlinear distribution model of lateral resistance under flexible load, while the latter adopts the linear lateral resistance distribution model and adopts the superposition principle to calculate the pile-soil stress ratio of long-core stirred pile. The results show that the lateral resistance segment nonlinear distribution model increases the vertical load sharing ratio of pile under the flexible load of high fill embankment. The larger the pile diameter and the longer the pile length, the greater the pile-soil stress ratio. The influence of pile length on pile soil stress ratio is greater than that of pile diameter. The results can provide references for similar study.