Loading　and　reaction　devices　are　often　used　in　quasi-static　tests　in　civil　engineering.　When　the　load　is　applied　by　an　actuator,　friction　force　will　be　generated　between　the　actuator　and　reaction　device.　The　friction　force　will　have　an　influence　on　the　test　results,　especially　on　the　pseudo-dynamic　test　and　the　hybrid　test　which　need　to　update　the　displacement　online.　However,　there　are　few　reports　on　the　influence　of　friction　on　seismic　test　and　few　methods　to　remove　friction.　Therefore,　the　influence　of　friction　on　the　parameters　of　seismic　test　is　studied　through　theoretical　analysis　in　this　paper,　and　a　method　to　remove　friction　from　the　measured　data　is　developed　to　reduce　the　influence　of　friction　on　the　quasi-static　test.　©　2022,　Editorial　Board　of　World　Earthquake　Engineering.　All　right　reserved.