Abstract: Three improved measures,i.e.increase of sampling amount,adjustment of extractive order for removing the interferential substrances and treating temperature were employed in this study based on classic extractive method.Thus a new pretreatment method for determining free aminoacids in tea-improved extractive method has been developed.The experimental results showed that,this method has high gathering rate and repeatability,less interfernce and is suitable for type 835-50 Auto-aminoacid Analyser.