Terminal　velocity　and　drag　coefficient　are　the　core　parameters　of　particle　motion,　but　their　predictive　models　and　measuring　methods　have　rarely　been　focused.　In　this　work,　terminal　velocity　and　drag　coefficient　models　for　disc　shaped　particles　are　proposed　based　on　the　imaging　experiment.　Experimental　devices　include　particle　sedimentation　and　video　image　acquisition　systems.　A　total　of　120　disc-shaped　particles　sedimentation　are　investigated.　Results　show　that　terminal　velocity　closely　relates　to　the　shape,　size　and　density　of　the　particles.　Thus,　particle　shape　factors　should　be　considered　in　the　drag　coefficient　model.　The　proposed　models　fitted　by　the　LM　+　UGO　optimization　algorithm,　have　more　accuracy　and　stability　than　the　published　models.　The　present　study　is　applicable　for　the　disc-shaped　particles　in　the　ranges　of　sphericity　phi　=　0.56-0.77,　flatness　ratio　d(a)　/d(v)　=　0.65-1.21,　circularity　psi　=　0.59-1,　and　Reynolds　number　Re　=　323-10,800.　Furthermore,　the　imaging　measurement　method　can　be　extended　to　other　non-spherical　particles.(c)　2021　Elsevier　B.V.　All　rights　reserved.