<p>There are still many difficulties and challenges in the simulation of pile support during the dynamic characteristic test of combustion turbine generator (CTG) foundation model. To demonstrate the criticality of precise stiffness control of pile in model testing, this study first conducted a quantitative analysis of the influence of pile stiffness deviations on the dynamic characteristics of the foundation through theoretical and numerical analysis. Subsequently, a steel frame support (equivalent pile) was designed and implemented to replicate pile stiffness in CTG foundation model testing, using an integrated approach comprising Abaqus solid-element modeling, prototype stiffness measurements, and iterative design optimizations. Based on this, modal testing of scaled foundation was performed, and the experimental results were compared with two numerical models: one employing spring elements and the other utilizing solid-element frame supports as piles. The results show that the overall stiffness deviation of the pile foundation by 25% and the deviation of the 1/4 piles by 50% will lead to the unacceptable deviation of the dynamic characteristics of the foundation, and also change part of the natural vibration mode of the foundation. In the model test, the final average deviation of the triaxial stiffness of 24 equivalent pile frames is controlled within 5%. The modal test results of the scaled foundation with these frame supports are consistent with the numerical simulation results, and the average deviation of natural vibration frequency is less than 5%. Using steel frame support to simulate the pile of CTG foundation can effectively control the pile stiffness deviation, and also provides a feasible technical scheme for the pile simulation in other similar model tests.</p>