Objective：To investigate the clinical application of intracavitary electrocardiographic（EKG） guided peripheral inserted central catheter（PICC） tip location method. Methods：Totally 180 patients with lung cancer were randomly divided into control group （90 cases） and observation group （90 cases）. Then the observation group were subdivided into observation group 1 and 2 by punc－ture sequence. Routine post-procedure chest X-ray was used to confirm the peripheral inserted central catheter tip location for patients in control group while EKG method was applied for patients in observation group. Post-procedure chest X-ray combined with EKG method was employed in observation group 1 to double confirm the catheter tip location. Chest X-ray was used in observation group 2 only when patients’ P wave change was not observed. The catheter in place rate，operation time，PICC-related complication and pa－tients’ satisfaction were measured and compared between control group and observation group，observation group 1 and observation group 2. The catheter in best place rate was compared between control group and observation group 1. Results：The operation time is statistically shorter（z=6.364，P=0.000），but the catheter in place rate and patients’ satisfaction were statistically increased in observa－tion group than in control group（?字2=7.745，P=0.005；63.34%/96.67%，P=0.000）. The catheter in best place rate was lower in control group than in observation group 1（?字2=43.740，P=0.000）. There was no statistical difference in catheter-related complication between groups（P>0.05）. Conclusion：The EKG method is accuracy，safe and can effectively help the catheter in place as well as reduce the time from catheter insertion to infusion therapy. When P wave change can be clearly observed on EKG，routine post-procedure chest X-ray is unnecessary.