Objective To investigate the effects of two infusion fittings on obstruction of double-lumen PICCs. Methods About 100 patients with double-lumen PICCs treated in the department of oncology in our hospital from 2013 to 2015 were randomized according to simple data table into observation group and control group, with 50 cases in each group:in the observation group Kolafu needleless infusion connector (MC100) was used and in the control group high voltage double-lumen PICCs were connected to the end of the diaphragm closed transfusion needleless joint (Q-syte). The incidence rate of catheter obstruction between the two groups were compared. Result The incidence of obstruction in the observation group was significantly lower than that in the control group (P<0.001). Conclusion Kolafu needleless infusion connector (MC100) can reduce the obstruction rate of the connectors, worthy of promotion.