This study builds a ubiquitous emergency medical service (EMS) system with sensor devices, a smartphone, a webcam, Zigbee, and a 3.5G wireless network. To avoid excessive wiring, a Zigbee-based wireless sensor network within the ambulance records the patient's biosignals, which includes an electrocardiogram (ECG), pulse, blood oxygen content, and temperature. Those biosignals are then transmitted to the Server located in the hospital emergency room via 3.5G wireless network for immediate first-aid preparation. This process significantly enhances EMS quality. Our experiment demonstrates biosignal transmission in real time for EMS application. In the future, we will promote the proposed system to WiMAX network when it becomes more pervasive in Taiwan to offer a much higher data throughput.