This case reports in a nursing experience of a patient with major depression, who makes herself and her family powerless due to a long termnegative thinking, with cognitive bias and self-harm behaviors many times. By using physical, psychological, mental, social and spiritual function assessments in the nursing process, the authors found out the patient's health problems included: risk for self mutilation, ineffective individual coping and ineffective family coping due to negative thinking and cognitive bias. After an established therapeutic nurse-patient relationship, the authors accomplished ten times cognitive therapies and also encouraged the patient's sister to participate in this therapeutic project. Finally, the patient improved her emotional problems, reduced self-mutilation behaviors and promoted her individual and family coping ability. This case report shows that when caring for major depressive disorder patients, nurses can even use cognitive therapy and independent nursing intervention to help patients and their families achieve a stable, and comfortable condition.