Abstract: Soil-structure interaction (SSI) in transmission towers has garnered growing attention in seismic research.Traditional analysis assumes fixed-base connections inaccurate assessment of seismic resistance because it neglects SSI effects.To investigate the seismic response of transmission towers with SSI,a finite element model of an ultra-high voltage transmission tower in Jiangsu Province,China,was established in SAP2000.Transmission line effects were considered using attached masses and loads,and pile foundation models were established.Multilinear elastic 1-joint links at pile shafts and ends simulate pile-soil interaction.Link properties derived from relevant specifications and site-specific soil parameters.Three single tower models were established:a fixed-base model (neglecting SSI),an SSI model with end-bearing piles,and an SSI model with friction piles.Time-history analyses subjected the models to natural ground motions,comparing structural responses.Results show that SSI increases average maximum responses:tower top displacement by 14.9%,inter-segment displacement ratio (ISDR) by 81.0%,and main member axial forces by 6.4%.Maximum tower top acceleration and maximum total displacement ratio (TDR) also increase.Therefore,ignoring SSI overestimates transmission tower seismic capacity,and SSI should be considered in seismic analysis.