The present invention provides a method for algorithm adjustment applying a motion sensor in a Continuous Glucose Monitoring system and a system using the method, comprising sensing an activity level of a patient by a motion sensor and providing signals to a processer, then adjusting a series of related algorithms depending partly on the signals by the processer to provide more accurate and reliable blood glucose related data that is the basis of desirable treatment plans； and automatically operating the CGM system including switching the system to an audio-off mode or pausing a calibration of the glucose sensor by the processer.
