ObjectiveTo evaluate the effect of different subclavian vein catheterization methods on catheterrelated bloodstream infection(CRBSI) in critically ill patients. MethodsPatients with subclavian vein catheterization for more than 7 days in the intensive care unit of a hospital between May 2008 and December 2015 were investigated retrospectively. They were divided into three groups: ultrasoundguided catheterization group(group A), conventional single lumen subclavian vein catheterization without skin expansion group(group B), conventional  double lumen subclavian vein catheterization group(control group). The survey included name, age, diagnosis, APACHE II score, catheterization sites and methods, whether or not succeeded in single catheterization, duration of catheterization, occurrence of CRBSI, and isolation of pathogens. Incidence of CRBSI, CRBSI per 1 000 catheterdays, and distribution of pathogens causing CRBSI were compared respectively among patients with different catheterization methods. ResultsA total of 2 366 patients were surveyed (group A, n=789; group B, n=786; control group, n=791). In group A, B, and control group, 13,15, and 40 cases developed CRBSI respectively, incidence of CRBSI were 1.65%, 1.91%, and 5.06% respectively，incidence of CRBSI per 1 000 catheterdays were 1.09‰, 1.27‰, and 3.36‰ respectively， the percentage of success in single catheterization were 97.47%, 88.80%, 87.23% respectively. There were significant difference in incidence，incidence of CRBSI per 1 000 catheterdays, and percentage of success in single catheterization among three groups(all P<0.01). Pairwise comparison showed that percentage of success in single catheterization in group A was higher than group B and control group, difference were significant (χ2 =46.25, 58.50，both P＜0.01）；incidence of CRBSI in control group was higher than group A and B(χ2 =12.82, 18.35 respectively，both P＜0.01）；incidence of CRBSI per 1 000 catheterdays in control group was higher than group A and B(χ2 =13.74, 11.22 respectively， both P＜0.01）. 13, 15, 40 strains of pathogens were isolated from three groups, Staphylococcus epidermidis and Staphylococcus aureus were the main pathogens in three groups, the proportion of coagulase negative staphylococcus infection in control group was higher than group A and B. ConclusionCompared with conventional catheterization methods (single lumen, double lumen), ultasoundguided subclavian vein catheterization can effectively improve the success rate of puncture. Ultrasoundguided catheterization and conventional single lumen subclavian vein catheterization without skin expansion can reduce the occurrence of CRBSI compared with double lumen subclavian vein catheterization.