Objective To explore the effect of immersive virtual reality technology applied in PICC placement on mood states and physiological parameters of breast cancer patients, and to provide a non-pharmacological strategy for improving clinical nursing quality. Methods A total of 100 breast cancer patients undergoing PICC placement were randomly divided into a control group and an observation group, with 50 cases in each. The control group received routine PICC placement, while the observation group was given immersive virtual reality-based intervention during PICC placement. The virtual reality contents mainly included seascape, cultural landscape, and cartoon and animated panoramic resources. The mood states, heart rates, and blood pressure at pre- and post-insertion of PICC, as well as pain score and insertion time were compared between the two groups. Results The observation group had significantly lower mood states score, lower heart rates and blood pressure at post-intervention, lower pain score, and shorter insertion time compared to the control group (all P<0.05). Conclusion The application of immersive virtual reality technology in breast cancer patients during PICC placement can effectively alleviate their negative emotions, stabilize heart rates and blood pressure, relieve pain, and shorten insertion time.