This paper introduces a monitor that can monitor five physiological parameters (ECG, blood pressure, spo2, respiration and temperature) based on Wireless Sensor Networks. The monitor will be applied to hyperbaric oxygen chambers. After acquisition, the signal will be displayed on the LCD screen of the monitor terminal in the cabin. At the same time, the Zigbee RF module will send the signal to the extravehicular guardianship PC terminals. This monitor equipment can realize synchronous real-time monitoring both inside and outside. What's more? A host can also display monitoring data the three monitor terminals collected. Preliminary clinical tests show that the monitors are safe and the monitoring results are satisfactory.