This paper compares the response spectrum method for seismic analysis of underground structures with the simplified analysis method （such as the response displacement method and the response acceleration method） suggested by the seismic code. First， the response spectrum method， the response displacement method， and the response acceleration method are briefly introduced. Then， taking the two-dimensional cross-sectional seismic analysis of three subway stations as an example， the accuracy of the three analysis methods is compared. The results obtained from the dynamic time-history analysis is used as the reference solution. The results show that the error of the response spectrum method is 0.1% to 14%， that of the response acceleration method is 0.2% to 26%， and that of the response displacement method is 9% to 44%. The accuracy of the response spectrum method is higher than both that of the response acceleration method and the response displacement method.