In Karst area, if the thickness of karst cave roof at the bottom of pile does not meet the stability requirement, the pile should pass through the underlying karst cave and insert the floor of the karst cave to increase the vertical bearing capacity of the pile. However, there is no mature method to calculate the vertical bearing capacity of this type of pile at present. This paper firstly uses laboratory test method to study progressive failure process and modes of the “formation-pile-cave” system under the condition of multi-stage loading at pile top. Secondly, based on collapse arch theory, this paper provides an approach to calculate the height of collapse arch, and the arch effect to the pile lateral friction is found out. Next, based on small-strain theory, critical condition of the axial buckling is established for the pile under the action of unidirectional compression, further, calculation method of axial loading for pile body is proposed. At last, procedures of calculating the vertical bearing capacity of the pile traversing karst cave is put forward and the proposed method in this paper is used to calculate the vertical bearing capacity of a realistic traversing-cave pile. Keywords: socketed pile; collapse arch; traversing karst cave; roof failure; pile lateral friction; vertical ultimate bearing capacity.