To solve the design problem of single pile crossing karst caves in practice，the bearing capacity of a single pile crossing unfilled karst cave was analyzed in this paper. Based on the field geophysical and laboratory test results，the distribution of the karst cave and the physical and mechanical parameters of rock and soil were deter? mined. Fourteen groups of numerical calculation models were established by using finite element software to capture the bearing characteristics of a single pile crossing an unfilled karst cave under different conditions of cave radius， cave position and pile diameter. The applicability of the BoxLucas1 load transfer model was verified by using numeri? cal results. A calculation method was then proposed to predict the response of a single pile crossing unfilled karst caves. The present study showed that the influence of karst caves on the bearing capacity of a single pile was weak? ened by increasing pile diameter and filling karst caves，and the radius and position of karst caves had a significant influence on the single pile bearing capacity. For practical purposes，the accurate exploration of karst cave distribu? tion should be paid attention to，which was beneficial to reducing the influence of karst caves on single pile bearing capacity. The proposed calculation method can provide a theoretical basis for parameter design and estimation of the bearing capacity of a single pile in the karst area.