This study was to develop a usability-engineered mhealth application for a mother with new-born baby and to evaluate its acceptance. Baby’s Health Handbook and hospital consultation service records were analyzed to design the contents of app. Special interface design principles were used for enhancing usability. App data were transmitted to an Excel-based server for management. Systems were evaluated in a 800-bed medical center in Taiwan with a questionnaire designed based on the Technology Acceptance Model for Mobile Service. 64 post-partum women were invited to use and evaluate the system and services at the next day after babies were delivered. The evaluation results indicated an overall satisfying perception with an average of 3.98 (SD= 0.71). The subjects perceived the system meeting their expectations, needs and the majority were willing to pay for service up to $6 per month. The mhealth appears having a great potential as an important health service model.