摘要：Objectives:This study aimed to explore the effectiveness of the theory-based tailored mHealth physical activity(PA)intervention among patients with breast cancer undergoing ***:A quasi-experimental study design was adopted.A total of 60 breast cancer patients were selected from two tertiary hospitals in Shanghai and Hangzhou City from September 2019 to August *** to the admission order,30 patients werefirst included in the control group,followed by 30 patients in the intervention group.A smartphone application(app)named“Breast Care”was developed based on social cognitive theory,self-efficacy theory,and the theory of planned *** app integrated various functions,including information browsing,PA monitoring and feedback,symptom reporting,and social *** in the intervention group received three months of personalized online PA guidance in addition to routine *** control group received routine *** and post-intervention investigations after three months were conducted in two groups using the Short Form of International Physical Activity Questionnaire,the Hospital Anxiety and depression Scale,and the Functional Assessment of Cancer TherapydBreast ***:After three months of intervention,compared to the control group,breast cancer patients in the intervention group showed significant improvements in walking,moderate PA,and overall PA(P<0.05).Compared to the baseline data,breast cancer patients in the intervention group had significant improvements in walking and overall PA after three months(P<0.05),whereas the control group experienced significant declines in walking,moderate PA,and overall PA after three months(P<0.05).There were statistically differences between the two groups in scores for anxiety,overall quality of life,and its dimensions,such as physical well-being,emotional well-being,and additional breast cancer well-being(P<0.05).Conclusions:The theory-based tailored mHealth PA interventio