Objective To investigate the effect of the continuing quality improvement on PICC-related phlebitis in breast cancer patients undergoing chemotherapy. Methods Eighty breast cancer patients undergoing PICC for chemotherapy in our hospital from September to December 2014 were selected as control group, receiving routine nursing care. Another eighty patients undergoing PICC for chemotherapy from January to March in 2015 were selected as experiment group and the quality control cycle was used, the measures including investigating the present situation aiming to theme, goal setting and analyzing, working out and using countermeasures and effect comfirming. Result After applying continuing quality improvement in the experiment group the incidence rate of phlebitis in the continuing quality improvement group was significantly lower than those before continuing quality improvement and in the control group (P<0.05). Conclusion The implementation of continuing quality improvement activities can reduce the incidence of pzce-related phlebitis in patients with breast cancer during chemotherapy. It can improve the safety of PICC catheter and therefore, it is worthy of popularization.