Abstract: The determination of the top reaction of different pile and the inter pile soil reaction are performed using the field plate load test in a composite foundation including mixed pile to study the variation of the pile soil stress ratio and the failure mode for this new type of composite foundation. By comparing with the in situ test data of the simple piles and the inter pile soil, this paper analyzes the reduction coefficient and the influence factor for the bearing capacity of each type of pile and the inter pile soil.