Objective To investigate the current status and to evaluate the usability of the ehealth applications in older patients with breast cancer. Methods A mixed method was used in the study. We investigated the usage of mobile programs among 236 older patients with breast cancer and the System Usability Scale was further used. In addition，semi-structured interviews were conducted with 13 older patients with breast cancer who used mobile medical programs. Results A total of 122 patients（51.69%） did not use the ehealth application，64 patients（27.12%） were assisted by family members，and only 50 patients（21.19%） reported that they used it. The reasons that older adults did not use mobile programs included having no knowledge of these medical programs applications （n=88） and being not able to use（n=76）. Logistic regression analysis showed that the education level，type of caregiver，and stage of treatment were independent factors of the use of the ehealth applications in older patients with breast cancer（P<0.05）. The total score of the App System Usability Scale was（58.05±13.97）. Two themes and five sub-themes emerged from the interview data：positive experience of App use（comprehensive platform functions，convenience and practicality，targeted and credible scientific contents）；limitations of the App and suggestions for improvement（operation methods need to be improved，more interactive design，the program interface needs to be improved for aging，and the integration of emotional support）. Conclusion Older patients with breast cancer do not pay much attention to the existing applications，and the system usability of the mobile medical application among them is low. The operation level and interface of the applications are low. The application needs to be improved according to the characteristics of the older adults.