BACKGROUND Low detection and nonadherence are major problems in current management approaches for patients with suspected atrial fibrillation (AF). Mobile health devices may enable earlier AF detection and improved AF management. OBJECTIVES This study sought to investigate the effectiveness of AF screening in a large population-based cohort using smart device-based photoplethysmography (PPG) technology, combined with a clinical care AF management pathway using a mobile health approach. METHODS AF screening was performed with smart devices using PPG technology, which were made available for the population >= 18 years of age across China. Monitoring for at least 14 days with a wristband (Honor Band 4) or wristwatch (Huawei Watch GT, Honor Watch, Huawei Technologies Co., Ltd., Shenzhen, China) was allowed. The patients with "possible AF" episodes using the PPG algorithm were further confirmed by health providers among the MAFA (mobile AF app) Telecare center and network hospitals, with clinical evaluation, electrocardiogram, or 24-h Holter monitoring. RESULTS There were 246,541 individuals who downloaded the PPG screening app, and 187,912 individuals used smart devices to monitor their pulse rhythm between October 26, 2018, and May 20, 2019. Among those with PPG monitoring (mean age 35 years, 86.7% male), 424 (of 187,912, 0.23%) (mean age 54 years, 87.0% male) received a "suspected AF" notification. Of those effectively followed up, 227 individuals (of 262, 87.0%) were confirmed as having AF, with the positive predictive value of PPG signals being 91.6% (95% confidential interval [CI]: 91.5% to 91.8%). Both suspected AF and identified AF markedly increased with age (p for trend <0.001), and individuals in Northeast China had the highest proportion of detected AF of 0.28% (95% CI: 0.20% to 0.39%). Of the individuals with identified AF, 216 (of 227, 95.1%) subsequently entered a program of integrated AF management using a mobile AF application; approximately 80% of high-risk patients were successfully anticoagulated. CONCLUSIONS Based on the present study, continuous home monitoring with smart device-based PPG technology could be a feasible approach for AF screening. This would help efforts at screening and detection of AF, as well as early interventions to reduce stroke and other AF-related complications. (Mobile Health [mHealth] Technology for Improved Screening, Patient Involvement and Optimizing Integrated Care in Atrial Fibrillation [MAFA II]; ChiCTR-OOC-17014138) (C) 2019 by the American College of Cardiology Foundation.