Objective To explore whether the replacement frequency of central venous catheter dressing has an effect on the incidence of skin bacterial colonization under the dressing. Methods A total of 29 children indwelling central venous catheter from PICU and CICU were taken as an experimental group, the dressing wasn′t replaced after 24 hours of the first indwelling of the central venous catheter, until the 7th day of the indwelling catheter; and other 28 children of their counterparts were regarded as a control group, whose dressing was replaced after 24 hours of the first indwelling of catheter, and was changed again on the 8th day of the indwe-lling catheter.When the dressing was replaced, the skin under the dressing was sampled at the 7th day for the experimental group, and at the 8th day for the control group, to compare skin bacterial colonization of the two groups. Results There wasn′t significant difference in the incidence of skin bacterial colonization between the two groups （P＞0.05）.Totally 228 sample sites were cultiva-ted in the two groups, and skin bacterial colonized in 61 （26.75%） of the sites; and there weren′t significant differences in positive rate in each sample site between the two groups （all P＞0.05）.Central venous catheter-related bloodstream infection and medical adhesive skin injury weren′t observed in the two groups. Conclusion When indwelling central venous catheter under strict sterile barrier, not replacing the dressing after 24 hours of central venous catheter placement will not increase the incidence of skin bacte-rial colonization under the dressing.