Abstract: Objective To explore the application effect of psychological nursing based on family counseling in patients with breast cancer undergoing modified radical mastectomy. Methods A total of 140 patients with breast cancer undergoing modified radical mastectomy in Zhejiang hospital from January 2018 to December 2019 were selected as the research objects. They were randomly divided into intervention group and control group, with 70 cases in each group. The control group was given routine postoperative care, and the intervention group was given psychological nursing based on family counseling on the basis of the control group. Self-rating depression and anxiety scale(SAS, SDS), simplified quality of life scale(SF-36), Pittsburgh sleep quality index(PSQI) and self-made questionnaire were used to compare the psychological status, quality of life, sleep quality and nursing satisfaction between the two groups. Results Before the intervention, there was no significant difference in the scores of depression and anxiety and sleep quality between the two groups(all P>0.05). After the intervention, the scores of depression and anxiety in the intervention group were(24.37±2.21),(26.58±2.71), and(2.3±1.4) on the 7 th day after the operation, which were significantly lower than those of the control group(35.01±5.02),(37.12±3.55) and(4.6±1.3) and lower than those of the control group before and after the intervention. Before and after the end of the intervention, the quality of life scores of patients in the intervention group(85.74±6.27, 85.37±6.33, 86.72±6.22, 87.12±6.74, 85.78±6.52, 87.01±6.34, 85.87±6.67, and 86.75±6.71) in the intervention group were significantly higher than those in the control group(65.36±4.75, 66.27±5.08, 64.37±4.27, 64.31±4.73, 64.21±4.78, 64.25±5.02, 65.11±5.23, and 65.62±5.37) scores of the control group(all P<0.05). After treatment, the nursing satisfaction of the intervention group was 92.85%, and that of the control group was 78.57%. The intervention group was significantly higher than the control group(P<0.05). Conclusion Psychological nursing based on family counseling can effectively improve the psychological status of patients with breast cancer after modified radical mastectomy, which is worthy of clinical research and application.