A　random　fiber　laser　is　achieved　based　on　the　plasmonic　feedback　mechanism,　which　is　constructed　by　first　siphoning　the　polymer　solution　doped　with　silver　nanoparticles　into　a　300-mu　m　capillary　tube　and　then　evaporating　the　solvent.　Strong　amplification　of　the　radiation　can　be　obtained　by　employing　the　variable　gain　region,　the　fiber　waveguide　scheme　and　three-dimensional　plasmonic　feedback　provided　by　the　silver　nanoparticles.　Low-threshold　directional　random　lasing　is　observed　in　the　polymer　fiber.　This　simple　and　straightforward　approach　facilitates　the　investigation　of　plasmonic　random　fiber　lasers.　(C)2016　Optical　Society　of　America