To research the work characteristics of the large-diameter rock-socketed cast-in-place pile under the load at river port and considering the layout features of the Cuntan phase Ⅲ project in Chongqing,we select the S1# and S2# to carry out in-situ pile tests,and analyze the mechanical mechanism,generation process of skin frictions and tip resistance of piles by the equivalent curve.Meanwhile，the indoor model test is made to study the stress mechanism.The test results show that skin frictions vary linearly,which will be produced when the pile-soil displacement reaches 8 mm,and frictions from rock vary nonlinearly,in which the maximum value is related to the characters of rocks,and generally locates at the place with high rock strength and near the pile tip.