Abstract: This is a research result :Firest - retrieve rate of combination for orthogonality design is use Three eliminote impurity reagent of ZTC 1+1; use three 0.1% active carbon powder; use 90% ethanol. Analyze result of the method and difference: Use number of times factor of eliminote impurity reagent of ZTC 1+1; Use number of times factor of 0.1 % active carbon powder, Factor of ethanol consistency all attain standard of maximal notable. It is had reference value in Increase extraction pureness research of effective composition for Gastrodia elata BL.

Key words: Gastrodia elata BL, extraction pureness