Horizontal storage tanks are extensively utilized in natural gas gasification, peaking, and refueling stations within the infrastructure sector. To investigate the impact of soil-structure interaction (SSI) on the seismic behavior of horizontal storage tanks in seismic regions, this study focuses on a specific type of horizontal storage tank. It employs a systematic parameter model to delineate the dynamic characteristics of soil foundation and develops a numerical simulation model of horizontal storage tanks with varying filling coefficients to incorporate the SSI effect. Three near-field seismic acceleration records from the PEER database were analyzed to assess the seismic response, including base shear, tank stress, and tank top acceleration. The findings indicate that higher filling coefficients result in a rise of base shear by 69% to 115%, an elevation of tank stress by 10% to 18%, and a reduction in tank top acceleration by 8% to 32%. Moreover, it underscores the significant influence of the SSI effect on the dynamic response. Consequently, designers should meticulously account for the effects of SSI in the design of horizontal storage tanks situated in earthquake-prone regions.