Abstract: In this paper, the pile and soil stress and displacement of CFG pile composite foundation of high-speed railway are numerically simulated under rigid and flexible loading conditions. The numerical results indicate the settlement and the ratio of pile loading distribution in the flexible loading test are less than those in the rigid loading test. So there is a difference settlement between pile and soil. Field loading tests were carried out to study and validate results of the rigid and flexible loading tests of the CFG pile composite foundation. It was found that the composite foundation bearing capacity under railway flexible load was controlled by the soil between piles. The soil between piles was the first to damage, then the whole composite foundation failed. The test results show that the flexible loading test with cushion is available and can simulate the bearing capacity of CFG pile composite foundation more reasonable. The tests also provide a basis for the design of CFG pile composite foundation under flexible conditions.