The performance of rectangular closed diaphragm walls (RCDW) subjected to earthquake ground motions is extremely complicated in gently sloping liquefiable deposits and requires further investigation. A nonlinear finite element (FE) model was developed to investigate the seismic performance of an RCDW in the OpenSees platform. Initially, the feasibility of the FE model to simulate the seismic behavior of the RCDW was validated by comparing the numerical results with the experimental data. The numerical results agree well with the centrifuge test data. Then, the calibrated model was used to study the seismic performance of the RCDW subjected to different ground motions in gently sloping liquefiable deposits. The numerical results indicate that the soil-RCDW system under near-fault ground motions is more likely to be damaged than that under far-fault ground motions. The difference between the maximum and minimum (Dmax-min) the RCDW displacement and the maximum excess pore pressure in the soil core increased as the Arias intensity increased. The seismic response of the soil-RCDW system was strongly affected by the frequency content, durations, energy distribution and initial directions of the ground motions. Moreover, the modified specific energy density (MSED) has a good linear relationship with the Dmax-min of the RCDW displacement.