Abstract: Based on the optimized pile viewpoint, the flexible pile and the rigid pile, the gravel pile and CFG pile are arranged in a group as compound piles, which utilizes their merits and avoids their shortcomings. Through analyzing the calculation methods for the bearing capability of composite foundation with multi-type piles, the reliability probabilistic analytical model of the bearing capability of a composite foundation with multi-type compound piles are set up. JC method is used in the calculation of reliability index of the composite foundation. Through engineering examples, the effects on reliability index from the variability of random variables are discussed.