Objective To sum up the experience of modified seldinger technique(MST) in the application of advanced cancer patients,and explore the superiority of MST.Methods 80 patients was divided into two groups,observational group use MST and vascular ultrasound guidance system,contrast group use traditional method.Results The first intubation success rate was 97.5%,and puncture bleeding、phlebitis were lower than contrast group(P0.015).There didn't have a dinstinct difference in catheter shift(P=0.152).Conclusion MST with ultrasound guided has a useful effect,it should be widely carried out in clinical,especially for those person whose vein isn't very well.