Objective To observe the effect of phlebitis prevention by thermotherapy with electric heating pad after peripherally inserted central catheter(PICC). Methods 100 patients underwent PICC were randomly divided into two groups, 50 patients receiving thermotherapy with electric heating pad were named the experimental group, other 50 patients only given routine observation was selected as the control group.The incidence rate of phlebitis was compared between the two groups and the results went through χ2 teat. Results The phlebitis rate of the experimental group was significantly lower than that of the control group. Conclusions Thermotherapy with electric heating pad can prevent phlebitis caused by peripheral-ly inserted central catheter (PICC) .