Abstract: Complex wavefields are not effectively considered in the random seismic response analysis of high-gravity dams. The random wavefield method generating the incident waves at the project site is proposed and the random seismic response analysis of the gravity dam is performed in this paper. To ensure the representativeness of the wavefield to site conditions, the wave information is generated and adjusted by comparing the response spectrum of the corresponding horizontal acceleration’s response spectrum at the reference point and the target spectrum. The non-uniform wave input method is utilized to realize the input of complex wavefields and the radiation damping of the foundation. A non-overflow dam section in Xiangjiaba gravity dam is chosen as an example to perform investigations considering the complex wavefield. The results show that the random wavefield method can provide incident waves fit for random seismic response analysis of gravity dams. Under the influence of complex wavefield corresponding to the design ground acceleration, the mean peak of major principal stress at the dam heel is 1.93 MPa, with the MSE 0.594 MPa and the variation coefficient 0.307. The mean peak of major principal stress at the downstream slopeface is 1.37 MPa, with the MSE 0.336 MPa and the variation coefficient 0.257. In these cases, the peaks of major principal stress at the dam heel are from 1.02 MPa to 2.95 MPa, which indicates that the failure probability of the dam heel element is 0.281%, according to the normal distribution of peak response.