Abstract: This paper presents the design of frequency_sampling FIR digital filter based on multirate conception for removal of base_line wander and power_line interference from the ECG. We can design high performance digital filter which can be used to resolve the problems involving present filters, such as difficulty of controlling cutoff frequency,large ripple in stop_band and pass_band, too narrow stop bandwidth for removing power_line interference, sensitivity to the fluctuation of power frequency, or the low frequency part of the ECG being cut off too much when removing base_line wander. This scheme can also avoid distortion resulting from non-linear filtering when compared with ⅡR digital filter or analog filter.