The periodical reservoir operation leads to a great change of physical properties of soft rock, thus affects the long-term load-bearing capacity of a rock-socketed pile. This paper investigates the axial load bearing capacity of rock-socketed pile with physical models under four working conditions, and gets the characteristics of axial force, pile side friction and end resistance of piles socketed in weak rock. On the basis of test data, this paper also conducts a 3D elasto-plastic finite element analysis for the axial bearing capacity, shaft friction, and end resistance of the piles with different lengths and diameters under three working conditions, which can provide a thereoretical basis and a practical method for designing piles socketed in weak rock in inland river reservoirs.