A blood pressure measuring system with automatic self-examination and self-calibration functions, which utilizes an examining and calibrating unit to automatically compare pressure information detected by a signal detection unit with an original factory calibration value for pressure, to self-calibrate the blood pressure measuring system, wherein the examining and calibrating unit can be arranged in a blood pressure measuring device or in an external electronic device, for providing users a method to confirm accuracy of the blood pressure measuring system to prevent serious consequence caused by miscalculations of blood pressure and physiological values. Accordingly, original factory calibration can be skipped to save time and money calibration and examination processes are simplified and more convenient.