Abstract: To assist the doctors in assessing drug effects and monitor the recovery of patients, the mobile medical monitoring system was designed in this paper, which utilizes electrocardiography (ECG) signals. ECG sensors were adopted to gather signals from monitoring sites. Both ECG signal acquisition and transmission were controlled by an ARM chip. GPRS network and Internet network were used for the remote wireless data transmission. In either a monitoring center or community hospital, SOCKET technology was utilized to develop network applications. The end-user friendly interface was visually established, and patient database and ECG database were administrated by the monitoring center with SQL database. When the sampling frequency of ECG sensors is 200 Hz, the Nyquist sampling theorem was satisfied and the acquisition precision is up to 5 mV, which can obtain accurate ECG P, Q, R, S, T waveforms. ARM processor has the merits of high performance, low power consumption and real-time analysis. The developed system not only realizes remote, real-time monitoring and alarming for ECG, but also provides the functions such as waveform playback and QRS waveform detection, which can be extended to other applications of physiological signal monitoring system.