Abstract: Objective To observe the effects of the improved ultrasound technology with out-of-plane orientation followed by in-plane guide for shock patients in ICU,and evaluate its safety. Methods Total 106 cases of shock in ICU were randomly divided into in-plane approach group (control group) and improved ultrasound group (experimental group).The patients in both groups were treated with intravenous sedation and analgesia.The radial artery puncture and catheterization in the control group was guided by in-plane approach,while in the experimental group by out-of-plane orientation followed by in-plane technique.One-time success rate and failure rate of puncture (punctured three times without success),time for puncture and incidence of complications were compared between the two groups. Results ①One-time success rate of the experimental group (81.3%) was significant higher than that (40.4%) of the control group,P<0.05.②The time for catheterization of the experimental group[(8.38±6.10) seconds]was significant shorter than that[(24.07±21.38) seconds) of control group],P<0.01.③The incidence of hematoma and puncture oozing of the experimental group (2.1% and 4.2%) were significant less than those (14.9% and 10.6%) of the control group,P<0.05. Conclusion Compared to the in-plane method,the improved ultrasound technology with out-of-plane orientation followed by in-plane guide for shock patients in ICU can improve the one-time success rate of puncture,decrease time for the puncture and reduce the incidence of complications.