Based　on　the　observation　of　overnight　hair　curling　procedure,　we　establish　a　mechanical　model　to　describe　the　temporary　wave　formation　of　straight　hair　(initial　curvature　is　zero),　which　incorporates　the　contact　between　hair　and　hair　roller.　Systematic　studies　are　carried　out　to　explore　the　effects　of　radius　ratio　between　hair　and　hair　roller,　hair＇s　average　axial　strain,　creep　time,　Poisson＇s　ratio　and　gravity　on　the　curl　retention.　The　variation　of　curl　retention　with　respect　to　time　obtained　from　our　numerical　model　is　validated　by　a　simple　theoretical　model　and　by　overnight　curling　experiments　on　hair　samples.　The　results　of　simulation　show　that　overnight　hair　curling　is　suitable　to　create　a　wavy　hairstyle　within　about　7　hours,　while　the　combined　usage　with　hair　fixatives　enables　a　wavy　hairstyle　with　desired　curvature　that　lasts　for　a　day　or　more.