The invention provides a positioning system, an apparatus, and a method for wireless monitoring of esophageal pH value, comprising: an internal transmitting apparatus 30, and an external recording apparatus 20 the external recording apparatus comprises a second means 203, and the second means 203 of the external recording apparatus 20 cooperates with the first means 307 of the internal transmitting apparatus 30 and if the external recording apparatus 20 detects that the internal transmitting apparatus 30 is not in the preset region, an alerting action is triggered under the control of the micro-processor 201 the external recording apparatus 20 periodically detects the intensity of the signal received by second wireless transceiver module 204, under the control of the micro-processor 201, and if it is detected that the signal intensity is not in the preset range of signal intensity, the alerting action is triggered under the control of the micro-processor 201.
