Abstract: The analysis and calculation show that low-pass Butterworth filters, Bessel filters and 3- dB Chebyshev filters have respectively a phase delay of -90°, -74.2°and -114.4°at the cutoff frequency, while their stopband attenuation is respectively -40, -35.9 and -43 dB/oct, where the input frequency is ten times the cutoff frequency. For frequency above 40 kHz, low-pass filters with an MFB(multiple-feedback) structure has better performance than those with an S-K(Sallen- Key) structure. As a result, the design of anti-aliasing filters can be optimized.