We　have　combined　cooperative　hunting,　inspired　by　recent　experimental　studies　on　birds　and　vertebrates,　to　develop　a　predator　-prey　model　in　which　the　fear　effect　simultaneously　influences　the　birth　and　mortality　rates　of　the　prey.　This　differs　significantly　from　the　fear　effect　described　by　most　scholars.　We　have　made　a　comprehensive　analysis　of　the　dynamics　of　the　model　and　obtained　some　new　conclusions.　The　results　indicate　that　both　fear　and　cooperative　hunting　can　be　a　stable　or　unstable　force　in　the　system.　The　fear　can　increase　the　density　of　the　prey,　which　is　different　from　the　results　of　all　previous　scholars,　and　is　a　new　discovery　in　our　study　of　the　fear　effect.　Another　new　finding　is　that　fear　has　an　opposite　effect　on　the　densities　of　two　species,　which　is　different　from　the　results　of　most　other　scholars　in　that　fear　synchronously　reduces　the　densities　of　both　species.　Numerical　simulations　have　also　revealed　that　the　fear　effect　extends　the　time　required　for　the　population　to　reach　its　survival　state　and　accelerates　the　process　of　population　extinction.