Abstract: Objective: To explore the practice of peripherally inserted central catheter (PICC) in patients with severe diseases. Methods: 2580 patients with severe diseases were performed PICC from January 2015 to June 2016. New vascular grading standards were established. Blind insertion technology, ultrasound guidance technology, ultrasound catheter position preliminary judgment method and electrocardiogram (EKG) positioning special conversion clamp were applied during PICC. Results: For the 980 patients with severe vascular injury (38.0%), the successful rate of the blind insertiontechnology and the ultrasound guidance technology was 99.1 and 99.9% respectively. For the 851 patients with severe systemic edema (33.0%), the successful rate of the blind insertiontechnology and ultrasound guidance technology was 99.0% and 99.7% respectively. For the 439 patients with skin laxity (17.0%), the successful rate of the ultrasound guidance technology was 99.7%. For the 310 patients with severe limb contracture (12.0%), the successfulrate of the ultrasound guidance technology was 99.7%. Conclusion: The improved PICC technology can enhance the successful rate of catheterization in patients with severe diseases.