Abstract:The extraction of polyphenols from hemp seed oil and folin-ciocalteu （FC） method for the determination of total phenolic content were optimized.The optimized method was as follows that 0.5 mL 80% ethanol solution was added to 0.25 mL oil sample，which was mixed at room temperature（25℃）and centrifugated at 4 000 r/min for 15 min，and then extracted for three times and combined with upper phase volume to 1.5 mL.The standard curve was drawn with gallic acid as the standard，3.5 mL 0.1 mol/L folin phenolic reagent was added to the polyphenolic extract of hemp seed oil，and 2.5 mL sodium carbonate solution with 7.5% mass concentration was added after the reaction for 10 min.The absorbance was measured at 765 nm after the reaction in dark for 1 h.This optimized method was evaluated with gallic acid as a standard，the results showed that gallic acid had a good linear relationship with the absorbance within the mass concentration range of 10 μg/mL to 80 μg/mL（r2=0.998 6）.The recovery rate of the method was（104.41±1.98）%，the relative standard deviation（RSD）of the same sample was 2.20% for 6 times determination，and 0.92% for absorbance within 0-3h，with good repeatability and stability，which could be used as an effective method for the analysis and determination of the content of phenolic oil concomitant in hemp seed oil.