Abstract: OBJECTIVE To study the migration of phthalate esters in single use infusion set into injections. METHODS Twenty-one injections were divided into 6 groups based on their properties. All injections were prepared as actual concentration needed by clinic and dripped through single use infusion set for 2 h at the rate of 40 drops per minute. The phthalate esters of the collected solution were detected by DLLME-GC-MS. The effect of excipients and contact time on the migration of phthalate esters were studied as well. RESULTS Phthalate esters were found migrating into 12 injections dripped through single use infusion set. The maximum migration amount of DBP or DEHP was detected in Amiodarone Hydrochloride injection. The amount of DBP in injection was 2.67 μg, while DEHP was 104.8 μg. Excipients such as tween-80, ethanol, propanediol and benzyl alcohol might accelerate the migration of phthalate esters. The migration amount of phthalate esters increased with the increasing of excipients amount. With the prolonging of contact time, the migration amout of phthalate esters would increase as well. CONCLUSION Phthalate esters in single use infusion set may migrate into injections with which the infusion set come into contact. The migration amount is related to the amount of tween-80, ethanol, propanediol and benzyl alcohol in injections, as well as contact time.