A micro displacement measurement system based on laser high order feedback effect is designed,and its principle is introduced.Also,the key parameters of optical system,mechanical part and single process units are given.Then,comparison tests are carried out for laser high order feedback system and PI moving stage.Test results show that the system resolution is up to 0.7 nm,and the errors of measurement system are analyzed.Measurement system based on laser high order feedback effect has the advantages of high resolution,simple structure and high cost performance,which has broad application prospect in precision measurement field.