Objective To explore the multidisciplinary collaborative extended care combined with EBN to improve breast cancer liver metastasis patients' psychological status and self-care ability. Background In the past ten years, the number of breast cancer patients with liver metastases has increased year by year, becoming a global public health problem. Studies have shown that 30% of breast cancer patients with liver metastases show varying degrees of anxiety and depression, and their quality of life is significantly lower than that of the normal population. Multidisciplinary collaborative continuous care can improve the prognosis of breast cancer treatment to a certain extent and is the key to meeting the needs of cancer patients. Materials and Methods The clinical data of 96 patients with liver metastases from breast cancer were selected as the study subjects and divided into a comparison group and an observation group of 48 cases each according to a random number table. Among them, the comparison group implemented evidence-based nursing (EBN) and the observation group implemented multidisciplinary collaborative extended care based on the comparison group. The effects of psychological status, quality of life, self-care ability, and sleep quality were compared between the two groups before and after nursing care. Results After nursing, the sleep quality scores, increased awakening scores, sleep quality that shows weakness because important things are not steady or strong scores, and night terrors scores of the two groups of breast cancer patients with liver the spread of diseases through the body were very much improved, and the sleep quality scores of the instance of watching, noticing, or making a statement group were much lower than those of the comparison group (P < 0.05). After nursing, the fear and stress-related score, depression score, tiredness and distress score, and anger score of the two groups of breast cancer patients with liver (the spread of diseases through the body) were very much improved, and the mental state score of the instance of watching, noticing, or making a statement group was much lower than that of the comparison group (P < 0.05). The scores of self-care skills, self-responsibility, health knowledge, and self-idea of patients in the instance of watching, noticing, or making a statement group after nursing were higher than those in the comparison group (P < 0.05). After nursing, the scores of mental energy, social interaction, emotional restriction, and mental status of patients in (instance of watching, noticing, or making a statement) were much higher than those in the comparison group (P < 0.05). Conclusion Multidisciplinary collaborative continuous nursing combined with EBN can effectively improve the sleep quality and psychological state of patients with breast cancer and liver metastases and improve self-care ability.