Abstract: Objective To evaluate the operation methods of PICC placement under ultra-sound guidance with modified Seldinger technique.Methods 140 PICC patients with cancer chemotherapy from were randomly divided into seldinger group and control group.In the seldinger group,83 patients were treated with modified seldinger technique to place PICC under ultrasound guidance.In the control group,57 patients were treated with conventional PICC.Success rate of PICC,puncture site bleeding,retention time,extubation reason,and incidence rate of complica-tion were detected.Results The retention time was higher in the seldinger group than that in the control group and the complication rate was lower in the seldinger group than that in the control group.The results revealed that the difference was statistically significant(P <0.05).Extubation reason of experimental group was lower than that in the control group,which showed no statisti-cally significant (P >0.05).Conclusion PICC placement under ultrasound guidance with modi-fied Seldinger technique is a secure and reliable method.It could overcome the difficulties of the poor condition of the blood vessels,improve the patient comfort,reduce the incidence of complica-tions,increase PICC retention time and improve the quality of life of cancer patients.