Abstract: Objective: To explore the effects of the target controlled infusion(TCI) for propofol combined with low density isoflurane in children undergoing minor operation.Methods: Forty-eight ASA grade Ⅰ-Ⅱchildren aged 2-6 yr weighting 11.5-25 kg,scheduled for hernia surgery were randomly divided into three groups with 16 cases in each:Ketamine group(group A),propofol TCI group(group B),and propofol TCI combined with low density isoflurane group(group C).The children in group A were given only Ketamine during operation.Heart rate(HR),respiration rate(RR) and pulse oxygen saturation(SpO₂) were recorded before induction(T₀),skin incision(T₁),dragging peritoneum(T₂) and sewing skin(T₃).All children's reaction at the time of skin incision and dragging peritoneum was recorded.Results: Compared with T₀,HR and RR at T₁,T₂ in group A significantly rised(P<0.05-P<0.01),but the variation of SpO₂ was not significant(P>0.05).In group B,compared with T₀,RR significantly rised at T₁(P<0.01),but HR,RR and SpO₂ declined at T₂ compared that of in group A(P<0.05).In group C,HR and RR decreased significantly at T₁,T₂ and T₃ compared with those in group Aand group B(P<0.05-P<0.01) and SpO₂ declined at the same time compared with group A(P<0.05).The children' SpO₂ in the three groups all exceeded 98% with oxygen inhaling.The time of regaining consciousness in group C reduced significantly compared with that in group A and group B(P<0.05).Conclusions: Propofol TCI combined with low density isoflurane in preschool chileren who accepted general anesthesia is safe and satisfied with the life sign stableness and a short revival time.