Abstract: To establish a method for the determination of ketamine and MDA and their main metabolites in urine by solid phase microextraction-liquid chromatography-mass spectrometry. In a urine sample supplemented with quantitative ketamine, norketamine, MDMA and MDA control. The solution was adjusted pH 11, added solid Na₂CO₃, heated and stirred at 60 °C. Then, the sample was extracted by SPME with 60 μm polydimethylsiloxane-vinylbenzene copolymer(PDMS/DVB ), a middle-polar coated fiber for 15 minutes and then analyzed by HPLC-MS. The result showed good linearity in the range of 0. 03-1. 0 μg/mL, r≥0. 999 2, and LOD was 0. 01 μg/mL, the value of the average recovery rate was varying from 97. 19%-105. 44%, and RSD was within 10%. The method is simple, safe and accurate, and can be used to determine ketamine, MDMA and their main metabolites in urine.