Aiming at PSD conversion circuit in laser triangulation range-finding,the noise model of displacement conversion circuit is established.The sensitivity of various components is analyzed and the multi-program is computed for the circuits formed by the cross-combination of the components with different performance parameters.The influence of component′s performance on the circuit noise is analyzed.Experiments are carried out.The results show that the study provides a valuable reference for the noise reduction method used in the practical measurement circuit design.It can be used to improve the resolution of the range-finding system effectively.