This system can realize the digital programmable filter and also could intercalate the gain of amplifier, the passband parameter and cut-off frequency of LPF or HPF could be intercalated. The hardware uses MCU(AT89C52)as the core to control the system, it consist of the PGA103、MAX262、the four-order elliptic low-pass filter and DDS an so on. The amplifier uses the PGA103, the fixed gain of amplifier is 60dB, the AT89C52 control the AD7520, it could realize the controled 10dB gain, the error has 5%. The LPF and HPF are realized by the programmable switched-capacitor filter integrated chip MAX262, the chip is controled by the AT89C52, the voltage gain of amplifier and filter is 30 dB in the 2fc, DDS theory is adopted to produce Amplitude-frequency characteristics tester. The design of the system is simple, it is very convenience.