Abstract: Multiple-feedback phenomena and generation mechanism were studied systematically based on asymmetric external cavity. When the reflectivity of feedback mirror was higher than 90%, the multiple high order feedback fringes were obtained owing to the stacking effect of many high order feedback beams going back to laser resonator. These feedback fringes have the features of unevenness and high resolution. Furthermore, the single high order feedback effects were discovered, and according to this ,the light-path-blocking method was presented . The fringes of single high order feedback have the advantages of both evenness and high resolution of /10, which is important for developing high accuracy measurement system.