Abstract: In order to detect the pollution of phthalic acid ester in cooking oil, the method for determination of phthalic acid ester from cooking oil by RHPLC is presented. The sample is dissolved in hexane and purified by Florisil solid-phase extraction column. Then it is measured by HPLC, using external standard method for quantitative analysis. In the scope of 0. 1-2. 0 mg/L, it has good linear relationship (r > 0. 99984); lowest detectable limit smaller than 50 ng/mL; the recovery rate of the phthalic acid ester at 0. 5 μg/mL, 1. 0 μg/mL and 8. 0 μg/mL addition ranged from 96% -104. 4%, the relative standard deviation was 1. 4% -2. 8%. The relative standard deviation of sample experimental precision was within 1. 4%. The results show that this method is simple, rapid, stable, sensitive and accurate for qualitative and quantitative determination of phthalic acid ester in cooking oil.