The　segmentation　of　a　specific　object　in　a　single　frame　image　has　been　faced　with　the　problem　of　low　segmentation　accuracy　due　to　background　complexity　and　illumination　variation.　In　this　paper,　a　shape　prior　local　binary　fitting　(LBF)　based　on　contour　pre-positioning　was　proposed　for　segmentation　of　human　upper-limb　images.　Firstly,　the　upper-limb　contour　template　was　selected　and　pre-positioned　by　a　kind　of　shallow　convolutional　neural　network,　and　the　coarse　contour　was　obtained.　Then,　the　LBF　algorithm　based　on　a　prior　shape　was　used　to　evolve　the　coarse　contour,　and　the　precise　contour　was　obtained.　Experimental　results　show　that　the　success　rate　of　the　algorithm　is　over　90%,　which　shows　that　the　method　has　good　effect　on　the　segmentation　of　a　specific　object　in　a　single　frame　image　faced　with　background　complexity　and　illumination　variation.　©　2017,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.