A lightweight convolutional neural network (CNN) is presented in this study to automatically indentify atrial fibrillation (AF) from single-lead ECG recording. In contrast to existing methods employing a deeper architecture or complex feature-engineered inputs, this work presents an attempt to employ a lightweight CNN to confront current drawbacks such as higher computational requirement and inadequate training dataset, by using representative rhythms features of AF rather than raw ECG signal or handcrafted features without any electrophysiological considerations. The experimental results suggested that this method presents the following significant advantages: (1) higher performances for indentifying AF in terms of accuracy, sensitivity, and specificity that are 97.5%, 97.8%, and 97.2%, respectively; (2) It is capable of automatically extracting the shared features of AF episodes of different patients and would be much robust and reliable; (3) with the cardiac rhythm features as input dataset, rather than complex transforming and classifying the raw data, thus requiring a lower computational resource. In conclusion, this automated method could analyze large amounts of data in a short time while assuring a relative high accuracy, and thus would potentially serve to provide a comfortable single-lead monitoring for patients and a clinical useful tool for doctors. INDEX TERMS Atrial fibrillation, cardiac rhythms, convolutional neural network, deep learning, electrocardiogram, single-lead recording.