In order to realize portable electrocardiogram (ECG) monitoring, a real-time ECG monitoring device based on the BMD101 chip was designed and implemented. The device comparison and selection, circuit filtering and printed circuit board analog-digital separation design were implmented to minimize power consumption and suppress noise interference. Some filter based denoising algorithms are used to eliminate common noises such as possible residual baseline drift, EMG noise, and power frequency interference. Experiments show that the designed system can acquire high quality ECG signals and the algorithm has a good denoising effect. The equipment has the characteristics of low cost, small size, easy operation, and good stability, which can provide a portable equipment for personal ECG monitoring.