The flexural bearing capacity of shield tunnel segments is crucial for tunnel construction, as sufficient flexural bearing capacity ensures the overall stability and safety of tunnel engineering. Currently, there is insufficient research on the flexural bearing capacity of shield tunnel segments. This study employs a standardized method for detecting the bending capacity of shield tunnel segments, complemented by full-scale bending tests, to evaluate the bending capacity of segments in the Longgang shield section of the Shenzhen Shantou Railway. The effectiveness of the full-scale bending tests was verified using standard design calculation methods, and the bending capacity of the segments under eccentric compression was further analyzed through finite element numerical simulation methods. The results indicate that as the load is applied closer to the end of the shield tunnel segment, the pressure that the segment can withstand increases. The bending bearing capacity required at the center of the segment gradually decreases, while the bending bearing capacity required at the end initially increases and then decreases. When the ultimate bearing capacity that the segment can withstand under ideal conditions is applied to various eccentric working conditions, the displacement at the center of the segment gradually decreases, and the displacement at the endpoints shows a trend of initially increasing and then decreasing.