Abstract: Objective: To investigate the effect of remifentanil on the effect compartment concentration(EC),response entropy(RE),state entropy(SE) and hemodynamical response during propofol target-controlled infusion(TCI) general anesthesia period.Methods: Twenty-two ASA classⅠ-Ⅱ patients undergoing elective surgery were randomly divided into the experimental group and control group,eleven cases in each group.In the two groups,the plasma concentration was as the target objective to do TCI.The initial plasma concentration was set to 1.5 μg /ml,increased by 0.5 μg /ml every 4 minutes until the Modified Observer Assessment of Alertness and Sedation(MOAA/S) score=1.The patients in experimental group were received with remifentanil infusion at 0.2 μg·kg^-1·min^-1,while the patients in control group were received with normal saline at 0.2 μg·kg^-1·min^-1.Tracheal intubation was operated after 3 minutes with muscular relaxants when MOAA/S was equal to 0.Propofol EC,RE,SE,mean arterial pressure(MAP) and heart rate(HR) were recorded when anesthesia was inducted with propofol TCI,including before anesthesia(T₀),at the time of infusion with muscle relaxants(T1),at the time of intubation(T₂) and at 1 min after intubation(T₃).Results: Propofol EC in experimental group was lower than that in control group at T₁-T₃(P< 0.05 to P< 0.01).There was no significant difference of RE and SE at T₁-T₃ between the two groups(P >0.05).MAP at T₃ and HR at T₁-T₃ in experimental group were lower than those in control group(P< 0.01).Conclusions: The doseage of propofol was decreased obviously during induction of general anesthesia by infusing remifentanil and propofol.At same time,HR and BP were inhibited obviously,but no changes of RE and SE.