A method to determine a real-time blood pressure reference value according to the blood pressure fluctuation factor can determine a blood pressure state by the ratio of the blood pressure measurement value to the blood pressure reference value, and to display the blood pressure reference value, the blood pressure measurement value and the description information of the blood pressure state by the output device. The system, applying the method, includes a mobile terminal and a medical health monitoring system. The application program of the method is downloaded and installed through network connection and APP store or I/O device, so as to describe the user's blood pressure status based on the real-time blood pressure reference value, and report the blood pressure status information and medical advice to the user via network connection.