Aiming at the asymmetric distribution of defects in the pile shaft of large-diameter pile foundation， employing the numerical simulation method， three-dimensional finite element pile-soil models are established for analyzing the dynamic responses of the pile. The different influence laws of symmetrical defects and asymmetric defects on the dynamic responses at the pile top are studied. The rationality of the numerical models is verified by comparing the simulated results with the test ones. In addition， the sensitivity analysis is conducted to study the effects of the parameters， such as soil around the pile and the excitation width and defect shape， on the dynamic responses of asymmetric defect piles. The results show that the dynamic response at the pile top of the symmetrical measuring points presents a double closed-loop phenomenon when asymmetric defects exist. The symmetrical measuring point with the most obvious double closed-loop phenomenon is located on the symmetry axis of the defect section. The mode of central excitation on the pile top and synchronous receiving of the symmetrical points can be used to detect the asymmetric defects of the piles， which can guide the engineering application of the low-strain integrity testing.