Abstract: In recent years, the impact of soft soil on the seismic response of soil layers in sites has attracted attention. Some scholars have conducted in-depth analysis from different perspectives, and the research results show that soft soil increases the dominant period and response spectrum characteristic period of the site to a certain extent. As the position of the soft interlayer deepens, the amplification effect of the site decreases, and the dominant period and response spectrum characteristic period of the site increase. Compared with the Code for Seismic Design of Buildings （GB 50011−2010） in China, the characteristic period of the seismic acceleration response spectrum for sites containing weak soil layers after regulation is much larger than the value specified in the code. At present, although there is an analysis of the impact of weak soil layers on site seismic response, there is little research on the adjustment methods of characteristic periods of site response spectra containing weak soil layers.Based on the analysis for the effect of site conditions on earthquake damage and the influence of soft layers on site seismic response at home and abroad, 12 site models are established, by means of drilling data from sites containing soft layers. The one-dimensional equivalent linearization site seismic response analysis is carried out under different input acceleration peak, and the influence of soft layer thickness, buried depth and input peak acceleration on site seismic response is discussed. The results show that under the same input acceleration peak, as the burial depth and thickness of soft layer increase, the characteristic period of the site acceleration response spectra gradually increases and the peak ground acceleration decreases. As the input peak acceleration increases, while the thickness and burial depth of the soft layer remain unchanged, the characteristic period of the site acceleration response spectra and the peak ground acceleration increases. Finally an adjustment method for the characteristic period of site acceleration response spectra with soft layers was proposed.