A programmable capacitance-voltage converter circuit for detecting small capacitance signal was presented. This circuit was composed of balance capacitor arrays, capacitance transimpedance amplifiers, sample/hold circuits, low pass filters and buffers. The capacitance detection method of modulation and demodulation was used to realize capacitance-voltage conversion. The simulation results showed that the capacitance resolution was 1.70 aF/Hz, the output voltage signal was proportional to the capacitance difference, and the determination coefficient R2 was 0.999 99. The integral capacitance value, amplification gain, balance capacitance and bandwidth of the circuit could be set flexibly by programming. The capacitance-voltage converter could be used for MEMS and other capacitive sensors.