Regarding the issue of determining the bearing capacity of pile foundations that traverse multiple karst caves in karst areas, indoor model tests were conducted on pile foundations crossing double layers of karst caves at different heights. The variation law of the ultimate bearing capacity of the pile foundation was obtained, and the failure modes of the pile foundation, karst cave roof, and partition were analyzed. And according to relevant specifications, the range of values for the stability coefficient of the pile body is provided. The research results indicate that; (1) The ultimate bearing capacity of pile foundation decreases with the increase of karst cave height. When reaching the critical hole height of 6 d (d is the pile diameter), The failure mode of the pile body is transformed from the compressive bulging failure of the pile top material to the buckling failure of the pile body.(2) The failure mode of the top plate and partition of the karst cave is related to the type of boundary conditions of the bedrock on both sides and the magnitude of the pile side frictional resistance. The overall failure mode of the karst cave roof and partition under the condition of fixed support at both ends is similar to the bending failure of the fixed support plate at both ends under concentrated load. A combined failure mode of local shear and punching shear occurs at the pile rock contact. (3) Under the premise of no damage to the rock and soil around the pile，when the karst cave height is less than 6 d, the pile top material is subjected to compression and swelling failure, and its ultimate bearing capacity depends on the material strength of the pile foundation itself. When the karst cave height is greater than or equal to 6 d, the pile body of the upper karst cave section undergoes buckling instability failure, and its ultimate bearing capacity depends on the buckling bearing capacity of the free section of the pile body.