Abstract: A device for accurately recording and presenting an electrocardiograph (ECG) signal collected by the non-optimal dry metal electrodes of wearable devices includes a first collecting module, a filtering module, a second collecting module, and a controlling module. The first collecting module collects a first ECG signal which is filtered to obtain a high frequency ECG signal and a low frequency ECG signal. The second collecting module collects the high frequency ECG signal and the low frequency ECG signal. The controlling module performs combination processing on the high frequency ECG signal and the low frequency ECG signal, then outputting an effective and accurate ECG signal. The present disclosure also provides a method for detecting and presenting an accurate electrocardiograph signal obtained by a wearable device.