Abstract: Objective To discuss the primary hazard factors of the phlebitis occurrence caused by PICC,provide the scientific evidences for the nursing staff adopting target - oriented prevention and the nursing measure.Methods The patient's common material whoused PICC the first time and laboratory examination indexes were collected and analyzed statistically.Results The single factor analysis result indicated there were some correlations between phlebitis's occurrence and the sex,the age,the puncture vein,the puncture number of times,the activity,the catheter pretreatment,blood sugar level; Using the chemotherapy medicine,the white blood cell count,the platelet count had nothing to do with phlebitis's occurrence.The multi -factor analysis result showed:Wants the vein,the catheter pretreatment was the protection factors,inserting the catheter repeatedly more time and age were the hazard factors which could cause the phlebitis' occurrence.Conclusions These factors should be paid close attention to in nursing work,the corresponding nursing measures should be taken to protect the PICC and reduce phlebitis's occurrence.