A non-invasive blood pressure measuring apparatus comprising: a host having a microprocessor coupled to an air pressure sensor; a pressurized cuff coupled to the air pressure sensor, and being an inflatable cuff with a gas tube, wherein the pressurized cuff is fastened to a body portion where user's artery blood flow is blocked completely after air inflation; a pulse wave detector connected with the host, wherein the pulse wave detector is fixed at a downstream position of the pressurized cuff according to the artery blood flow direction, and the pulse wave detector is used to detect changes of the pulse wave and senses in real-time changes in the blood flow pulse generated by the pressure variation of the pressurized cuff; characterized in that the microprocessor is configured to process in real-time a plurality of pulse wave amplitudes detected by the pulse wave detector during the course of slow increase from zero and the corresponding pressure in the pressurized cuff to thereby determine the systolic pressure, based on the amplitudes of the pulse wave near the systolic pressure substantially showing a linear variation; the microprocessor is further configured to perform a real-time process to several pulse delay periods which are the pulse delay periods between the pulse waves and the corresponding Alternating Current pressure signals during the course of variable pulse delay periods to relatively constant pulse delay periods and the corresponding pressures of the pressurized cuff to determine the diastolic pressure, based on the time characteristic of the pulse delay periods between the pulse wave and the corresponding Alternating Current air pressure signals near the diastolic pressure. a host having a microprocessor coupled to an air pressure sensor; a pressurized cuff coupled to the air pressure sensor, and being an inflatable cuff with a gas tube, wherein the pressurized cuff is fastened to a body portion where user's artery blood flow is blocked completely after air inflation; a pulse wave detector connected with the host, wherein the pulse wave detector is fixed at a downstream position of the pressurized cuff according to the artery blood flow direction, and the pulse wave detector is used to detect changes of the pulse wave and senses in real-time changes in the blood flow pulse generated by the pressure variation of the pressurized cuff; characterized in that the microprocessor is configured to process in real-time a plurality of pulse wave amplitudes detected by the pulse wave detector during the course of slow increase from zero and the corresponding pressure in the pressurized cuff to thereby determine the systolic pressure, based on the amplitudes of the pulse wave near the systolic pressure substantially showing a linear variation; the microprocessor is further configured to perform a real-time process to several pulse delay periods which are the pulse delay periods between the pulse waves and the corresponding Alternating Current pressure signals during the course of variable pulse delay periods to relatively constant pulse delay periods and the corresponding pressures of the pressurized cuff to determine the diastolic pressure, based on the time characteristic of the pulse delay periods between the pulse wave and the corresponding Alternating Current air pressure signals near the diastolic pressure.