Aimed at ECG health care for families,and improving the accuracy of the low power monitoring ECG monitoring system，an ECG monitoring system using Kalman filter is designed and implemented. The weak ECG signals are extracted by electrodes and ECG collecting line of three lead, and then filtered and amplified through the analog front using AD8232 , then the STM32 processor is used for Kalman filter processing. At last, the actual ECG characteristics of biological electrical signals and heart rate are got in the LCD.Tested by the experimental prototype,under the condition of the human body being quiet,the result in the LCD is clear and stable,and can reflect the actual electrical characteristics of the human body. The results show that the design successfully completed the ECG signal filter processing,can meet the needs of home ECG monitoring,which means a certain reference value for family medical equipment.