As　a　key　technology　in　modern　society,　face　detection　has　become　an　active　subject　in　the　field　of　pattern　recognition　and　computer　vision.　In　this　paper,　we　propose　some　applications　of　analyzing　crowd　attention　based　on　face　detection　technology　and　realize　a　crowd　attention　detection　system　using　Haar-like　features　and　Adaboost　algorithm.　The　system　consists　of　image　acquisition　module,　face　detection　module,　display　module　and　data　analysis　module.　At　the　same　time,　we　adopt　the　method　of　empirical　research.　Using　the　camera,　combined　with　software　named　AMcap,　the　system　captures　images　of　crowed　during　the　display　of　a　video　regularly.　Then,　the　system　detects　the　faces　which　are　being　concerned　about　this　attractive　video　in　images,　circling　and　counting　them.　In　addition,　the　system　displays　the　data　change　graph　of　the　crowd　face　at　different　moments,　and　finally　calculates　the　mathematical　expected　value　of　crowd　attention　for　further　processing　such　as　Big　Data　technology.　After　further　processing,　the　system　can　obtain　the　data　which　reflects　the　degree　of　concern　in　a　particular　sector.　Through　the　above　experiment,　Facts　have　proved　that　the　system　can　easily,　accurately　and　intuitively　detect　the　crowd　attention　data　and　has　great　value　in　many　sectors.　©　2017　IEEE.