Objective To investigate the risk factors of obstruction of central venous catheter(CVC)in the intensive care unit(ICU). Methods One hundred and thirty-three adult patients in ICU with CVC were included in the study. The difference of the position of catheters, duration of indwelling catheters,selection of sealing solution,blood platelet(PLT)count,prothrombin time(PT),international normalized ratio(INR),activated partial thromboplatin time(APTT),thrombin time(TT)and fibrinogen(FBG)were studied between two groups of patients(with and without the obstruction of CVC).Results In 117 cases,there were no catheter obstruction,accounting for 88.0%. Catheter obstruction occurred in 16 cases,accounting for 12.0%,10 cases of which the catheters were partially blocked,accounting for 7.5%and in 6 cases completely blocked,accounting for 4.5%.There were significant differences in the duration of indwelling catheters,PLT and FBG levels between the two groups of patients(all P<0.05).There was no significant difference in the position of catheters,selection of sealing solution and PT,INR,APTT,TT level between the groups(all P>0.05).Conclusion Prolonged time of indwelling CVC,high levels of PLT and clotting fibrinogen are the risk factors of the obstruction of CVC in ICU patients.