In　this　paper,　the　data　processing　methods　and　their　theories　for　analyzing　acceleration　records　obtained　from　strong　motion　observation　arrays　in　hydraulic　structures　are　introduced　in　detail.　The　data　processing　methods　include　seismic　source　assessment　method,　and　some　steps　of　data　pretreatment　process,such　as　data　calibration,　singular　points　eliminating,　baseline　correcting,　de-noising　by　a　filter,　and　first-order　and　second-order　integral　of　acceleration　and　spectrum　transform　which　belongs　to　data　routine　process.　The　calculation　principles　of　the　coefficient　assessment　of　earthquake　disaster　are　also　studied.　By　taking　a　case　study　of　strong　motion　data　recorded　at　Ertan　arch　dam　stations　as　an　example,　the　paper　pomts　out　the　steps,which　easily　go　wrong　in　data　processing.　And　the　corresponding　countermeasures　are　proposed.