Diseases in the gastro-intestinal track are becoming more prevalent. In order to diagnose a patient, the various signals of the digestive organ, such as temperature, pH, and pressure, can offer helpful information. The variation of a pressure signal of the gastro-intestinal track can offer information about digestive troubles or provide clues about diseases. This paper presents a wireless system for the pressure monitoring system, which includes a swallow-type pressure capsule and the external receiving system. A transmitter, a transmitting antenna (Helix), a receiver, and a receiving antenna (Loop) were designed and fabricated in consideration of the MPE, power consumption, system size, signal to noise ratio and modulation method. The wireless system designed and implemented for the pressure monitoring system was verified by in-vivo experiments. As a result, we found each organ has its own characteristic pressure fluctuation.