Li　et　al.　first　proposed　a　quantum　hash　function　(QHF)　in　a　quantum-walk　architecture.　In　their　scheme,　two　two-particle　interactions,　i.e.,　I　interaction　and　pi-phase　interaction　are　introduced　and　the　choice　of　I　or　pi-phase　interactions　at　each　iteration　depends　on　a　message　bit.　In　this　paper,　we　propose　an　efficient　QHF　by　dense　coding　of　coin　operators　in　discrete-time　quantum　walk.　Compared　with　existing　QHFs,　our　protocol　has　the　following　advantages:　the　efficiency　of　the　QHF　can　be　doubled　and　even　more;　only　one　particle　is　enough　and　two-particle　interactions　are　unnecessary　so　that　quantum　resources　are　saved.　It　is　a　clue　to　apply　the　dense　coding　technique　to　quantum　cryptographic　protocols,　especially　to　the　applications　with　restricted　quantum　resources.