Abstract: This paper studied the technique of agarose extraction with EDTA-Na2 method.The main factors discussed were: EDTA-Na2 concentration,extraction temperature and extraction time on influencing in sulfate radical content and gel strength.Using the response surface method to optimize the extraction process,the best parameters were EDTA-Na2 concentration 4.5 g·L-1,extraction temperature 65℃ and extracting time 3 h.With the optimized parameters,the sulfate radical content and gel strength of agarose extracted were 0.48% and 1 073.09 g·cm-2,respectively.The optimal extraction parameters were verified by repetitive tests with relative error <1.0%.It is suggested that EDTA-Na2 method is accurate and repeatable in using for agarose extraction.