Abstract： Objective To investigate the application of modified seldinger technique under guidance of vascular ultrasound combined with electrocardiogram(ECG)in peripherally inserted central catheters(PICC)catheterization in patients with blood diseases.Methods A total of 110 patients with blood diseases admitted to the First Affiliated Hospital of Guangxi Medical University from January 2021 to January 2023 were enrolled,and they were randomly assigned in a 1∶1 ratio to traditional seldinger technique(on the right side,the control group)or modified seldinger technique under guidance of vascular ultrasound combined with ECG(on the right side,the observation group)for 7 days.The puncture points,catheterization,drug dressing frequency,one-time success rate,bleeding volume of puncture point and complications of the two groups were observed.Results The incidence of puncture point bleeding,abnormal bleeding,and mechanical phlebitis in the observation group was significantly lower than that in the control group(P＜0.05).The time to completion of introducer sheath insertion in the observation group was significantly shorter than that of the control group,and the immediate pain degree of catheterization was significantly lower than that of the control group(P＜0.05).The 96h drug dressing frequency in the observation group was significantly lower than that in the control group(P＜0.05).The one-time success rate of observation group was significantly higher than that of control group(P＜0.05).There was no difference in blooding volume of puncture point between groups(P＞0.05).The incidence of complications(infection and fluid seepage)in the two groups was comparable(P＞0.05).Conclusion Modified seldinger technique under guidance of vascular ultrasound combined with ECG has a higher success rate,which can improve the puncture points,shorten the time to completion of introducer sheath insertion,and reduce pain,it is worthy of clinical promotion.