Ruby　single　crystals　with　a　diameter　of　7　mm　and　a　length　of　70　mm　were　successfully　produced　by　the　floating　zone　technique.　The　solid-liquid　interface　is　convex　to　the　melt,　and　growth　direction　was　determined　as　.　The　X-ray　rocking　curve　of　the　crystal　has　a　FWMH　of　0.089°,　proving　the　excellent　quality　of　the　crystal.　The　as-grown　crystals　were　characterized　by　polarized　optical　microscopy,　X-ray　diffraction,　chemical　etch,　scanning　electron　microscopy,　as　well　as　energy　dispersive　spectroscopy.　The　primary　crystal　defects　observed　were　bubbles,　dislocations,　cellular　Structure　and　solute　trails.　The　relationship　between　crystal　quality　and　growth　condition　was　also　discussed,　and　the　optimum　method　was　obtained.