High resolution accelerometer is a kernel sensor for gravity gradiometer measurement.The QFA is mostly used in this measurement at present,so the requirement of noise performance is very strict.Therefore,a new type low-noise QFA preamplifier is put forward to detect differential capacitor based on constant AC voltage stimulation.On such a basis,the integral servo circuit is designed in combination with the parameters of QFA and servo circuit calibration.The quantitative analysis of the noise influence of servo circuit has been done,the noise contribution of the circuit to the QFA servo system is approximately 1.0×10^-10 g/√Hz(0.5Hz) at 0.5Hz.This can satisfy the needs of gravity gradiometer measurement above 10E resolution.