The high-precision and low-latency data acquisition of displacement sensors is crucial for achieving high-precision and high-bandwidth fast steering mirrors. A detailed analysis of the requirements for the displacement sensor acquisition circuit in a composite axis with a fast steering mirror is provided, based on this, hardware circuit and software design are carried out. Through testing, the effective resolution of the acquisition circuit can reach 17 bits, the data frequency is 5 kHz, and the signal acquisition delay is 200 μs. The high-speed and high-precision acquisition of signals from fast steering mirror displacement sensors is realized, which can effectively enhance the control bandwidth and control precision.