An exercise physiological sensing system, a motion artifact suppression processing method and a motion artifact suppression processing device for obtaining a stable exercise heart rate signal of a user during exercise are provided. The exercise physiological sensing system includes a bone conduction body, a signal-to-noise ratio analysis module, and a computation module. The bone conduction body has a physiological sensor. The physiological sensor detects a physiological signal from a detected area of the user. The signal-to-noise ratio analysis module is coupled to the physiological sensor and detects a quality stability of the physiological signal. The computation module is coupled to the signal-to-noise ratio analysis module and generates the stable exercise heart rate signal according to the physiological signal. Accordingly, the exercise physiological sensing system can effectively improve the stability of the detected physiological signal during exercise.
