In　this　article　the　biodiesel　production　procedure　of　base-catalyzed　esterification　was　studied,　and　the　optimal　conditions　of　preparation　were　brought　up.　By　applying　orthogonal　design,　the　optimal　conditions　of　base-catalyzed　esterification　from　waste　frying　oil　with　acid　value　of　4　mg/l　KOH　were:　methanol/oil　ratio,　8:1;　catalyst　dose,　1%　oil　weight;　temperature,　85　degrees　C;　reaction　time,　1.5　h.　The　maximum　oil　conversion　rate　of　90%　was　achieved.　The　influence　of　each　factor　on　the　oil　production　in　descending　order　was:　methanol/oil　ratio　＞　catalyst　dose　＞　temperature　＞　reaction　time.　The　biodiesel　refinement　was　carried　out　with　three　types　of　rinsing　solutions:　distilled　water,　satirized　NaCl　solvent　and　glacial　acetic　acid.　Rinsing　times,　soap　removing　rate　and　final　acid　value　of　the　biodiesel　were　considered　as　the　critical　factors　in　evaluating　the　effectiveness　of　the　rinsing　solution　on　the　biodiesel　refinement.　The　results　turned　out　that　the　most　suitable　rinsing　method　for　industrial　application　was　rinsing　with　saturated　NaCl　solvent.