With the rise of edge computing and the improvement of computing power of edge devices, the edge of network has been given enough computing power and decision-making ability, and it can be used to provide intelligent services which have stronger real-time performance, faster feedback speed and higher reliability. The edge of the network is used as the application background for the study of ECG signal processing technology, and morphological filtering and smooth filtering are combined for denoising ECG signals. The R wave detection algorithm was based on the difference threshold method. The first-order difference square, filter the peak and updating threshold adaptively are used to reduce the influence of noise on the R wave detection algorithm and improve the accuracy of R wave detection. It shows that this algorithm has high reliability and real-time performance from the results.