Preset　layering　powder　containing　Ti+TiB2P,　coarse　TiB2P　and　fine　TiB2P　are　taken　to　prepare　TiB　short　fiber,　with　reinforcing　Ti-based　composite　coatings　on　the　surface　of　Ti6Al4V　through　laser　synthesis　in-situ.　Volume　fraction　and　length-diameter　ratio　of　TiB　short　fiber　are　analyzed　by　scan　electron　microscopy　(SEM)　and　X-ray　diffraction　(XRD).　The　results　show　that　the　coating　is　mainly　composed　of　TiB　short　fiber　and　TiB2P.　When　Ti+TiB2P　acts　as　a　preset　layer,　length-diameter　ratio　of　TiB　short　fiber　reduces　as　the　content　of　Ti　increases;　when　coarse　TiB2P　acts　as　a　preset　layer,　the　coating　is　difficult　to　form　a　large　volume　fraction　of　TiB　short　fibers;　when　fine　TiB2P　acts　as　a　preset　layer,　high　volume　fraction　and　large　length-diameter　ratio　of　TiB　short　fiber　can　be　formed　in　the　coating.　The　formation　mechanism　is　explained　through　microstructure　evolvement　rule　of　TiB　short　fiber　in　the　coating.