A hydraulic impact hammer comprises an impact hammer core, an outer shell, a pile cap set, a lifting oil cylinder, wear-resisting lining plates and a hydraulic system, and two guide frames of the outer shell are symmetrically arranged in the vertical direction of a frame body; two guide grooves of the impact hammer core are symmetrically formed in the vertical direction of the upper hammer core; apiston rod of the lifting oil cylinder is hinged to the upper end face of the upper hammer core; a cylinder barrel is hinged to the lower end face of an outer shell upper cover plate; the wear-resisting lining plates are arranged on the outer surfaces of the two guide frames; the pile cap set is fixedly arranged on a frame flange of the outer shell through an upper cap flange of an upper pile cap, and a lower pile cap is sleeved in the upper pile cap; a chopping board is arranged in a central counter bore in a manner of being higher than the end surface of the inner ring of the lower pile cap; and a buffer ring is mounted in a manner of being higher than the end face of a boss, and the upper plane of the buffer ring is tightly attached to the lower end face of the upper pile cap. The hammer has the advantages of being good in overall rigidity, small in movement resistance of the hammer core, resistant to impact of the chopping board, high in operation efficiency, low in manufacturingcost and use cost and the like.