The utility model relates to a life jacket used for providing the user floating on the surface with a sense similar to sitting in a chair so as to reduce the tiredness of the user floating on the surface for a long time. A riding crotch is added at the floating body bottom of the traditional life jacket to apply the buoyancy of the life jacket on the buttocks of the user through the riding crotch; and if a pedal is additionally arranged, the life jacket can also make the tired legs have a rest during swimming.