To study the influence of changes in composite foundation parameters on the settlement and load sharing ratio, an ANSYS finite element simulation model of the three-dimensional spatial contact between the CFG pile, soil and bedding layer was established based on a CFG pile composite foundation engineering project. The applicability and accuracy of the model were verified by combining it with field test data, and the influence of changes in parameters such as pile spacing and bedding layer thickness on the settlement of the composite foundation and the stress ratio between pile, soil and bedding layer was analysed. The results show that the calculated results of the established numerical simulation model are in good agreement with the measured results obtained in situ. The stress distribution on the upper surface of CFG piles under load shows non-uniformity, with the edge stress being visibly higher than the stress in the range of 0.5 times the pile diameter from the pile centre. Furthermore, the soil between the piles also shows non-uniformity within this range. The pile diameter on the pile side is significantly influenced by the pile penetrating into the bedding layer. Whilst the 0.8 m pile spacing has been shown to significantly reduce the bearing capacity of the foundation, it is not conducive to the optimum utilisation of the pile bearing capacity. It is also not conducive to the utilisation of both the pile spacing and the bedding layer. The pile spacing of 0.8 m can have a significant effect on the bearing capacity of the foundation, but this configuration is detrimental to the utilisation of the pile bearing capacity. It is recommended that the thickness of the bedding layer should be between 5 and 10 cm. This will act as an intermediate layer between the piles, reducing settlement.