Objective To investigate the effect of relaxation and inspiring psychological nursing on postoperative pain in patients undergoing plastic and cosmetic surgery. Methods A total of 44 patients undergoing plastic and cosmetic surgery in our hospital from January to December 2025 were selected, and they were divided into the control group and the study group by the random number table method, with 22 patients in each group. The control group received conventional postoperative nursing, and the study group received relaxation and inspiring psychological nursing on the basis of conventional nursing. The postoperative pain, dosage and frequency of analgesic drugs, anxiety and depression levels, postoperative recovery and patient satisfaction were compared between the two groups. Results The pain scores in the study group at 6 , 24 and 48 hours after operation were lower than those in the control group (P<0.05). The total dosage and frequency of postoperative analgesic drugs in the study group were lower than those in the control group (P<0.05). The scores of anxiety and depression in the study group were lower than those in the control group (P<0.05). The postoperative recovery time in the study group was shorter than that in the control group, and the complete recovery rate was higher than that in the control group (P<0.05). The patient satisfaction in the study group was higher than that in the control group (P<0.05). Conclusion Relaxation and inspiring psychological nursing can effectively relieve postoperative pain of patients undergoing plastic and cosmetic surgery, reduce the dependence on analgesic drugs, improve psychological state, promote postoperative recovery and enhance overall treatment satisfaction.